Year % of total population 1960 39.1268500159658 1961 39.018137570559006 1962 39.07680477897929 1963 39.48099716760927 1964 39.79923023208319 1965 39.86456116042791 1966 39.82458019734827 1967 39.60820686825852 1968 39.37637225405501 1969 39.20806388963173 1970 38.977795235795725 1971 38.7644502984353 1972 38.47594187543582 1973 38.1829202906899 1974 38.04707977756685 1975 37.94771785786814 1976 37.82251225026877 1977 37.39212941388526 1978 36.477205707876784 1979 35.53595180865377 1980 34.76097401507937 1981 34.071848787495625 1982 33.52735046298578 1983 32.918497112811615 1984 32.20608439129582 1985 31.547634203835504 1986 30.980553153053854 1987 30.549522982941195 1988 30.167693002192994 1989 29.83902806060118 1990 29.63773679837309 1991 29.43403194477755 1992 29.162684325394387 1993 28.872473668500934 1994 28.521013623296202 1995 28.097772719020714 1996 27.602813690402936 1997 27.007324337799524 1998 26.401919927391624 1999 25.8184439073801 2000 25.197107950567148 2001 24.50560701436271 2002 23.72726340355927 2003 22.966546950635745 2004 22.25105632815715 2005 21.523045530531846 2006 20.91894901277534 2007 20.506330006665262 2008 20.19331936866477 2009 19.95182782560459 2010 19.753185973637347 2011 19.592794220880545 2012 19.503459213240955 2013 19.458790453524642 2014 19.433276867346493 2015 19.392988740664027 2016 19.349901269799517 2017 19.342547042038884 2018 19.28929108951154 2019 19.162387685177453 2020 18.966682359986898 2021 18.700715828375447 2022 18.384371219352815 2023 18.029727593363347