Year % of total population 1960 38.5592013550582 1961 37.8323072121659 1962 37.2255713590032 1963 36.7401986541958 1964 36.3756801800303 1965 36.1301867413901 1966 36.0108268633328 1967 36.0108357475177 1968 35.3401394783724 1969 33.818341194146 1970 32.1678919903584 1971 30.6891176820613 1972 29.4643938032742 1973 28.4905762932967 1974 27.7623687508321 1975 27.2579380707185 1976 26.7983008155629 1977 26.5043622437792 1978 26.5570832735679 1979 26.8774392468943 1980 27.3177762207626 1981 28.0357305168245 1982 28.9150802838706 1983 29.6520241456756 1984 30.2797725803992 1985 30.780954327776 1986 31.1752760524206 1987 31.2672876416087 1988 30.9482523862144 1989 30.3802879666399 1990 29.6798176355938 1991 28.9288873365072 1992 28.1793197434496 1993 27.4499344213335 1994 26.727504740183 1995 25.9852912205625 1996 25.4659535474893 1997 24.9516726972998 1998 24.1121244176055 1999 23.1394809403392 2000 22.1747376526295 2001 21.3166589345282 2002 20.6117560158788 2003 20.0535054542575 2004 19.6018419673361 2005 19.0040115688099 2006 17.7431633627134 2007 16.0983318530183 2008 14.7291883043225 2009 13.8458500090834 2010 13.7447650968176 2011 14.0747305749542 2012 14.2593750618511 2013 14.3316711128707 2014 14.3343702146849 2015 14.3178587085039 2016 14.3286837398462 2017 14.3965147584791 2018 14.5293695045808 2019 14.7122010730534 2020 14.9409854694949 2021 15.1430338314588 2022 15.2321568337938 2023 15.216398330922