Year % of total population 1960 38.4826547750043 1961 39.06019391022 1962 39.6573194867575 1963 40.2869637107301 1964 40.9452921473763 1965 41.6027679072377 1966 42.2185699212726 1967 42.765671080498 1968 43.2191939468808 1969 43.550604542544 1970 43.7181632615532 1971 43.6240887707832 1972 43.2500175278693 1973 42.7903151184907 1974 42.3223360896328 1975 41.8049801041966 1976 41.1685241472476 1977 40.4260203273913 1978 39.7550720560193 1979 39.1430758643087 1980 38.5789445469792 1981 38.0706810253299 1982 37.478738616693 1983 36.8756403449075 1984 36.3948861105337 1985 35.9824864004246 1986 35.593381583473 1987 35.1926440385215 1988 34.6623937458235 1989 34.0078899669474 1990 33.2789169258483 1991 32.6646086950462 1992 32.2085974287805 1993 31.6434033173376 1994 31.1379840342336 1995 30.6723757275707 1996 30.1131700860357 1997 29.8674402043603 1998 29.6398588792748 1999 29.0988545406112 2000 28.5791906070447 2001 28.104772218257 2002 27.6459206511916 2003 27.1886065652216 2004 26.6967284231153 2005 26.2787746119721 2006 25.8717692581493 2007 25.4850013303217 2008 25.1399982151622 2009 24.7270130726134 2010 24.2667070669906 2011 23.8215012736206 2012 23.5707016126494 2013 23.476435676324 2014 23.3895572494158 2015 23.326279725917 2016 23.3303650934996 2017 23.368414849156 2018 23.3644678519122 2019 23.3231933699011 2020 23.2379418174927 2021 23.1552401839007 2022 23.103385502971 2023 22.9871818688464