Year % of total population 1960 27.438425782382 1961 27.3989793455382 1962 27.4229730714762 1963 27.3915983417331 1964 27.4143244678932 1965 27.5310787493572 1966 27.6544899397431 1967 27.7479169970303 1968 27.7947356895547 1969 27.850995827065 1970 27.8749452876053 1971 27.8521775392017 1972 27.7758320149637 1973 27.651836752992 1974 27.5068846082399 1975 27.3370013353586 1976 27.1837920318025 1977 27.0148668907215 1978 26.7587954931126 1979 26.3913801633278 1980 25.9622271787015 1981 25.4811569857962 1982 24.9498810612322 1983 24.4216101961343 1984 23.8783962676891 1985 23.305574559315 1986 22.6937697533279 1987 22.03735243474 1988 21.3548562902906 1989 20.6420749561141 1990 19.8839137854058 1991 19.1340973549726 1992 18.4469358461959 1993 17.7958914850633 1994 17.1640361929627 1995 16.5774250548913 1996 16.0532331945023 1997 15.5982386233745 1998 15.21612718524 1999 14.9108243473127 2000 14.6869070832831 2001 14.542694260092 2002 14.4729083647569 2003 14.464341401744 2004 14.4613763989692 2005 14.4690005400892 2006 14.5260294194217 2007 14.5956633040401 2008 14.7035045362781 2009 14.8474009059568 2010 14.9735760309309 2011 15.0766482201479 2012 15.1496388763887 2013 15.1885925463172 2014 15.1900219588908 2015 15.1562020326701 2016 15.0953337415246 2017 15.0091846115234 2018 14.8623367438776 2019 14.6477912843276 2020 14.3956333577662 2021 14.10691172214 2022 13.7978723714063 2023 13.46492562468