Year % of total population 1960 33.4448066467721 1961 33.411976903933 1962 33.0053583156496 1963 32.4392207301424 1964 31.819704054975 1965 31.1202417774922 1966 30.2990966592045 1967 29.4407213381304 1968 28.57572273617 1969 27.7311777154944 1970 26.8399017909184 1971 26.0127823141654 1972 25.3308944572002 1973 24.7386366011899 1974 24.3019135086388 1975 24.03521947251 1976 23.9444928332133 1977 23.9543986145426 1978 23.975605191849 1979 24.0645449857179 1980 24.2529826150857 1981 24.4669169026346 1982 24.710065124297 1983 24.9972284292042 1984 25.2715874972013 1985 25.4849696104615 1986 25.6020603792298 1987 25.5946467998132 1988 25.4537664104981 1989 25.224509662389 1990 24.9316993716506 1991 24.591139426214 1992 24.2168240627457 1993 23.7930177032347 1994 23.3144520825145 1995 22.7667260103988 1996 22.1799940252191 1997 21.5466626655689 1998 20.8254246441254 1999 20.0759322993357 2000 19.3285235146054 2001 18.6375248164505 2002 18.0256749751824 2003 17.4523078849464 2004 16.9230759464921 2005 16.4433822444271 2006 16.0159344472921 2007 15.6784015190746 2008 15.4564381312847 2009 15.3190517891263 2010 15.2288552015471 2011 15.1453138767257 2012 15.0710455777783 2013 15.0189487870218 2014 14.987170464575 2015 14.974587287896 2016 14.9936562652774 2017 15.0833022515979 2018 15.2032776849962 2019 15.2925703157779 2020 15.3480034078472 2021 15.3692941127502 2022 15.1505142283709 2023 14.9435173137177