Year % of total population 1960 31.995514164126828 1961 32.35393362814011 1962 32.42440579276941 1963 32.35347586014344 1964 32.09656341236459 1965 31.71618163033225 1966 31.331268010796336 1967 30.950535515855904 1968 30.55523916706287 1969 30.111127978912194 1970 29.617936017290116 1971 29.149860162047897 1972 28.728835327702917 1973 28.325824835910726 1974 27.945811242677497 1975 27.589792110881344 1976 27.27223008110054 1977 27.00273584820075 1978 26.761619665161877 1979 26.611066738924652 1980 26.573346132388018 1981 26.592437603867825 1982 26.6351907108313 1983 26.678005889394814 1984 26.741137062346034 1985 26.81371267648124 1986 26.86219372662672 1987 26.881384857504827 1988 26.86582557441609 1989 26.792235664873647 1990 26.659891914950062 1991 26.477179193636406 1992 26.257890599492086 1993 26.002846847462585 1994 25.709272293134994 1995 25.37412431143806 1996 24.99279382414089 1997 24.546950035482688 1998 24.008030547049355 1999 23.4127538945842 2000 22.810887936479855 2001 22.182322242029997 2002 21.53342084701367 2003 20.95725732297896 2004 20.486109748991833 2005 20.074957745188893 2006 19.73929052981028 2007 19.505868581109194 2008 19.396562110104558 2009 19.360434724442264 2010 19.34954829490663 2011 19.37120859476074 2012 19.4493141307899 2013 19.568665197307585 2014 19.71887263853639 2015 19.892379954566515 2016 20.06578435809463 2017 20.221272468867028 2018 20.34555613940888 2019 20.429160589096906 2020 20.48308348600031 2021 20.53202781308019 2022 20.610364698812834 2023 20.518272583095246