Year % of total population 1960 19.17545799535623 1961 19.513824251788435 1962 19.886875986966064 1963 20.265943958846112 1964 20.65568890673378 1965 21.058765119058965 1966 21.451272211813748 1967 21.50938950607086 1968 21.58096993042747 1969 21.666807124553493 1970 21.769012844752453 1971 21.89039201828531 1972 22.02331918774742 1973 22.15646838848412 1974 22.289946310574212 1975 22.413944816408183 1976 22.53422969781117 1977 22.59294568133025 1978 22.599156410826502 1979 22.58845126874927 1980 22.5612543646012 1981 22.529715371680705 1982 22.495201475539083 1983 22.439665440890373 1984 22.374443013430543 1985 22.30805624679892 1986 22.246479014702636 1987 22.28340288023469 1988 22.38112670848812 1989 22.49220907500672 1990 22.630659326119908 1991 22.80772841536044 1992 23.010049051876756 1993 23.221479516863194 1994 23.450498405859822 1995 23.697152432527993 1996 23.958826020421352 1997 24.049069190477056 1998 24.04376932937699 1999 24.046006425569693 2000 24.05893674089573 2001 24.074184212780636 2002 24.08180100161359 2003 24.090210272794547 2004 24.112881553618028 2005 24.145836418472467 2006 24.188438325494822 2007 24.229893775453057 2008 24.269801020297233 2009 24.31032320252763 2010 24.333521870621503 2011 24.312948285883323 2012 24.279299331252208 2013 24.23258760719481 2014 24.179182002103015 2015 24.15934935153309 2016 24.168273219672525 2017 24.20056055746323 2018 24.254922353811445 2019 24.301967404986566 2020 24.362569538135038 2021 24.440159887715215 2022 24.536985067938897 2023 24.638499114389525