Aging and sub-replacement fertility
Tracking birth rates, age structure shifts, migration offsets, and labor market consequences of demographic decline.
Updated today.
Age Structure
Absolute population level — the bottom line of births, deaths, and migration.
341.8T
Trend YoY growth is +0.7%, slowing by 1 bps/year over the last 64Y. Latest: +0.5%, 16 bps below trend, a 0.84σ deviation.
Level
YoY %
y = 1.3% − 1 bps/yr · t
Deviation from trend
Cleanest headline aging metric — share of the population that is elderly.
18.4%
Trend YoY growth is +0.3%, accelerating by 42 bps/year over the last 64Y. Deviations have remained above trend for 14 consecutive periods. Latest: +0.5%, 18 bps above trend, a 1.3σ deviation.
Level
YoY Change (bps)
y = 0.0% + 0 bps/yr · t
Deviation from trend
Best single metric for economic burden — ratio of 65+ population to working-age (15–64).
28.5%
Trend YoY growth is +0.5%, accelerating by 87 bps/year over the last 64Y. Deviations have remained above trend for 14 consecutive periods. Latest: +0.8%, 32 bps above trend, a 1.4σ deviation.
Level
YoY Change (bps)
y = −0.1% + 1 bps/yr · t
Deviation from trend
Births & Fertility
Core measure of replacement shortfall — 2.1 is the replacement level for developed countries.
1.63births/woman
Trend YoY growth is +0.0%, accelerating by 0 bps/year over the last 63Y. Deviations have remained below trend for 5 consecutive periods. Latest: +0.0%, 1 bps below trend, a 0.23σ deviation.
Level
Change (pp)
y = −0.1% + 0 bps/yr · t
Deviation from trend
Direct read on how many births are occurring at the population level per 1,000 people.
10.60per 1,000
Trend YoY growth is -0.0%, accelerating by 1 bps/year over the last 63Y. Latest: -0.1%, 8 bps below trend, a 0.29σ deviation.
Level
Change (pp)
y = −0.4% + 1 bps/yr · t
Deviation from trend
Rising longevity compounds the aging problem — more years in retirement per person.
78.89years
Trend YoY growth is +0.1%, slowing by 0 bps/year over the last 63Y. Latest: +0.5%, 42 bps above trend, a 0.95σ deviation. The latest YoY reading is depressed by 87 bps due to an tough comparison base from Jan '23.
Level
Change (pp)
y = 0.2% − 0 bps/yr · t
Deviation from trend
Labor & Economic
Whether economies are offsetting aging by extending working lives — key to fiscal sustainability.
36.9%
Trend YoY growth is +0.3%, accelerating by 97 bps/year over the last 65Y. Deviations have remained below trend for 40 consecutive periods. Latest: -1.1%, 1.4 pp below trend, a 2.7σ deviation.
Level
YoY Change (bps)
y = −0.4% + 1 bps/yr · t
Deviation from trend
Tracks how much the near-retirement cohort remains economically active as populations age.
64.5%
Trend YoY growth is +0.4%, accelerating by 70 bps/year over the last 48Y. Deviations have remained below trend for 12 consecutive periods. Latest: -0.2%, 59 bps below trend, a 0.49σ deviation. The latest YoY reading is depressed by 78 bps due to an tough comparison base from Jul '25.
Level
YoY Change (bps)
y = 0.0% + 1 bps/yr · t
Deviation from trend
Market signal on healthcare demand — aging populations drive structural growth in medical spending.
$175.4
Trend YoY growth is +5.4%, slowing by 1.1 pp/year over the last 9Y. Deviations have remained above trend for 79 consecutive periods. Latest: +29.1%, 23.8 pp above trend, a 3.2σ deviation. The latest YoY reading is boosted by 16.5 pp due to an easy comparison base from Aug '25.
Level
YoY %
y = 15.7% − 1.1 pp/yr · t
Deviation from trend
Key Insight
The U.S. aging problem is moving from forecast to crisis faster than expected, because the primary economic buffer — older workers staying in the labor force longer — is now breaking down at the exact moment the dependency ratio is hitting its steepest ascent.
Aging and sub-replacement fertility
Tracking birth rates, age structure shifts, migration offsets, and labor market consequences of demographic decline.
Updated today.
Age Structure
Absolute population level — the bottom line of births, deaths, and migration.
341.8T
Trend YoY growth is +0.7%, slowing by 1 bps/year over the last 64Y. Latest: +0.5%, 16 bps below trend, a 0.84σ deviation.
Level
YoY %
y = 1.3% − 1 bps/yr · t
Deviation from trend
Cleanest headline aging metric — share of the population that is elderly.
18.4%
Trend YoY growth is +0.3%, accelerating by 42 bps/year over the last 64Y. Deviations have remained above trend for 14 consecutive periods. Latest: +0.5%, 18 bps above trend, a 1.3σ deviation.
Level
YoY Change (bps)
y = 0.0% + 0 bps/yr · t
Deviation from trend
Best single metric for economic burden — ratio of 65+ population to working-age (15–64).
28.5%
Trend YoY growth is +0.5%, accelerating by 87 bps/year over the last 64Y. Deviations have remained above trend for 14 consecutive periods. Latest: +0.8%, 32 bps above trend, a 1.4σ deviation.
Level
YoY Change (bps)
y = −0.1% + 1 bps/yr · t
Deviation from trend
Births & Fertility
Core measure of replacement shortfall — 2.1 is the replacement level for developed countries.
1.63births/woman
Trend YoY growth is +0.0%, accelerating by 0 bps/year over the last 63Y. Deviations have remained below trend for 5 consecutive periods. Latest: +0.0%, 1 bps below trend, a 0.23σ deviation.
Level
Change (pp)
y = −0.1% + 0 bps/yr · t
Deviation from trend
Direct read on how many births are occurring at the population level per 1,000 people.
10.60per 1,000
Trend YoY growth is -0.0%, accelerating by 1 bps/year over the last 63Y. Latest: -0.1%, 8 bps below trend, a 0.29σ deviation.
Level
Change (pp)
y = −0.4% + 1 bps/yr · t
Deviation from trend
Rising longevity compounds the aging problem — more years in retirement per person.
78.89years
Trend YoY growth is +0.1%, slowing by 0 bps/year over the last 63Y. Latest: +0.5%, 42 bps above trend, a 0.95σ deviation. The latest YoY reading is depressed by 87 bps due to an tough comparison base from Jan '23.
Level
Change (pp)
y = 0.2% − 0 bps/yr · t
Deviation from trend
Labor & Economic
Whether economies are offsetting aging by extending working lives — key to fiscal sustainability.
36.9%
Trend YoY growth is +0.3%, accelerating by 97 bps/year over the last 65Y. Deviations have remained below trend for 40 consecutive periods. Latest: -1.1%, 1.4 pp below trend, a 2.7σ deviation.
Level
YoY Change (bps)
y = −0.4% + 1 bps/yr · t
Deviation from trend
Tracks how much the near-retirement cohort remains economically active as populations age.
64.5%
Trend YoY growth is +0.4%, accelerating by 70 bps/year over the last 48Y. Deviations have remained below trend for 12 consecutive periods. Latest: -0.2%, 59 bps below trend, a 0.49σ deviation. The latest YoY reading is depressed by 78 bps due to an tough comparison base from Jul '25.
Level
YoY Change (bps)
y = 0.0% + 1 bps/yr · t
Deviation from trend
Market signal on healthcare demand — aging populations drive structural growth in medical spending.
$175.4
Trend YoY growth is +5.4%, slowing by 1.1 pp/year over the last 9Y. Deviations have remained above trend for 79 consecutive periods. Latest: +29.1%, 23.8 pp above trend, a 3.2σ deviation. The latest YoY reading is boosted by 16.5 pp due to an easy comparison base from Aug '25.
Level
YoY %
y = 15.7% − 1.1 pp/yr · t
Deviation from trend