Year % of total population 1960 34.5514282695985 1961 35.1659267219854 1962 35.5227450264469 1963 35.546920539706 1964 35.2589726178093 1965 34.6616589902972 1966 33.9064072993484 1967 33.1651926593458 1968 32.429340353674 1969 31.6898097934205 1970 30.9529551566365 1971 30.2355666792933 1972 29.5425661224649 1973 28.8567513425687 1974 28.1788950750217 1975 27.532000063369 1976 26.9471372161084 1977 26.4764353069878 1978 26.1433649840114 1979 25.9690755776126 1980 25.9393674267164 1981 25.9952566450692 1982 26.1252159648027 1983 26.3596971473449 1984 26.6854094465629 1985 27.0013451314264 1986 27.2422350509701 1987 27.3939567948602 1988 27.4300366088628 1989 27.3164777149128 1990 27.0933084772918 1991 26.831584344214 1992 26.5462851025451 1993 26.2176243171256 1994 25.8328402127604 1995 25.3716490614755 1996 24.8343921655819 1997 24.2470878497934 1998 23.5722748461365 1999 22.7899104018123 2000 22.0921527161829 2001 21.5138622750001 2002 20.9054928077206 2003 20.3182866949586 2004 19.783590073179 2005 19.2831876586639 2006 18.8544766239181 2007 18.5082810936631 2008 18.2493569704508 2009 18.1075838930202 2010 17.9964254118742 2011 17.8565622099807 2012 17.7359769878483 2013 17.6710554757231 2014 17.829583686366 2015 18.197601260516 2016 18.5890739671014 2017 18.9441554268409 2018 19.2404157185748 2019 19.4759045773086 2020 19.6493213439759 2021 19.8060170703541 2022 19.3115573621233 2023 19.0548063974509