Year % of total population 1960 23.3591554135538 1961 23.3502646390264 1962 23.25186246219 1963 23.2003648989393 1964 23.2723559499828 1965 23.4187742109053 1966 23.597107849191 1967 23.7685470217328 1968 23.9069163246101 1969 24.016749103342 1970 24.1060352282331 1971 24.1543425257933 1972 24.1085403028263 1973 23.9455894358055 1974 23.6924717628779 1975 23.3498956334719 1976 22.9230905444882 1977 22.4351344941154 1978 21.9293955943134 1979 21.4546788715328 1980 21.0244754460117 1981 20.6259267692701 1982 20.2428159026658 1983 19.8859352897754 1984 19.5691479067698 1985 19.3097062429263 1986 19.0892693685609 1987 18.9366874738083 1988 18.8961986455836 1989 18.9326560317306 1990 19.0289089268974 1991 19.1720733531745 1992 19.3282175177415 1993 19.4505074702985 1994 19.4867735900972 1995 19.4496732318133 1996 19.4020708475748 1997 19.3599274920913 1998 19.3000274597212 1999 19.2058942748599 2000 19.0578244857202 2001 18.8694806080063 2002 18.6609902100371 2003 18.4502256243982 2004 18.261942132148 2005 18.0757571969932 2006 17.8972710542286 2007 17.7664640853784 2008 17.6908633916145 2009 17.6464813465497 2010 17.6278811556178 2011 17.6294357068589 2012 17.6421204892553 2013 17.6566554068823 2014 17.6723749575135 2015 17.7212237746005 2016 17.8003904732425 2017 17.8760575913004 2018 17.9083522707734 2019 17.8740875883716 2020 17.7883500845831 2021 17.6612097379976 2022 17.4667211276054 2023 17.2166712269646