Year % of total population 1960 37.8552885781044 1961 37.4214021465168 1962 37.0462390516649 1963 36.9510339103418 1964 37.0593023739116 1965 37.1754049650441 1966 37.7412257082093 1967 38.7970792268719 1968 39.6549912231062 1969 40.1504065494317 1970 40.4068806583023 1971 40.543608346205 1972 40.4413761910479 1973 39.9647324107316 1974 39.4209436909193 1975 38.9158849008554 1976 38.3568599125104 1977 37.7169159143236 1978 36.9113159272347 1979 36.0457475100981 1980 35.1877627752915 1981 34.2713523471977 1982 33.1955344603972 1983 32.0657402448613 1984 31.0095864806344 1985 29.9947240656859 1986 29.064683910774 1987 28.1639928430081 1988 27.4286991532377 1989 26.9692598409107 1990 26.6568462493864 1991 26.500057410342 1992 26.4712704403654 1993 26.4826143864815 1994 26.4904728744103 1995 26.4479969019282 1996 26.3416709237355 1997 26.197572099076 1998 26.0275158102743 1999 25.8305873678152 2000 25.5897773530298 2001 25.3061028502174 2002 24.9867223517419 2003 24.6503147282555 2004 24.3166751082407 2005 23.9525115615621 2006 23.534649891951 2007 23.0853431933135 2008 22.6329554232333 2009 22.1881943862763 2010 21.719790206245 2011 21.2387355049154 2012 20.8054638884882 2013 20.4290755804608 2014 20.1023110163678 2015 19.8277279509098 2016 19.5888723935156 2017 19.3871440285779 2018 19.2320393482377 2019 19.1085122384142 2020 19.0133633880735 2021 18.9482875517545 2022 18.8979450307221 2023 18.8450924601125