Year % of total population 1960 16.299724041584305 1961 16.69459666237353 1962 17.07784915791587 1963 17.488344887508433 1964 17.931781601044296 1965 18.393995818461033 1966 18.810029202631654 1967 19.10039825055186 1968 19.408091764337552 1969 19.727187728683145 1970 20.054777421205003 1971 20.397571532130932 1972 20.75725089052466 1973 21.119614704466915 1974 21.47180430127588 1975 21.775682306400956 1976 21.933820267543446 1977 22.060197950659678 1978 22.22917968168893 1979 22.383204576902113 1980 22.486108840212587 1981 22.51421819250364 1982 22.535785196915285 1983 22.575137614932377 1984 22.62060120844102 1985 22.693312129831533 1986 22.78905224465329 1987 22.831740406808184 1988 22.904564752361782 1989 22.966358567612946 1990 23.07821686821053 1991 23.165470703924523 1992 23.27046628471946 1993 23.40915802139394 1994 23.555863720828302 1995 23.658711652086257 1996 23.772695089328835 1997 23.84584366242025 1998 23.916513815211857 1999 23.989688553079407 2000 24.066559121381843 2001 24.14871075477189 2002 24.290545001848475 2003 24.411934041744335 2004 24.414686780993115 2005 24.42838776411933 2006 24.431334208923158 2007 24.419311893273868 2008 24.47724047925871 2009 24.545043529293416 2010 24.62009720514812 2011 24.406987945816343 2012 24.296959938491742 2013 24.22948095688803 2014 24.21567992196713 2015 24.41267159290374 2016 24.699903518342605 2017 24.877508612908237 2018 25.053334223661967 2019 25.102798200377364 2020 25.22145176337005 2021 25.369985276304586 2022 25.477272814899756 2023 25.56766482061056