Year % of total population 1960 40.328308851740715 1961 40.24444066179492 1962 40.3592716154098 1963 40.799586604640034 1964 41.177732046521356 1965 41.336775785960775 1966 41.39532652857892 1967 41.29468421845455 1968 41.16440099283009 1969 41.07717663906376 1970 40.930994936859 1971 40.78076216186231 1972 40.54493882441046 1973 40.30260151390486 1974 40.19476612113593 1975 40.1111196779037 1976 39.99507777397156 1977 39.5886681878381 1978 38.7327507258919 1979 37.839659350203064 1980 37.08516601665549 1981 36.39124113499413 1982 35.828938989949854 1983 35.21410384470253 1984 34.50612013689794 1985 33.850160496937086 1986 33.27105607392515 1987 32.81490328838331 1988 32.40862926289307 1989 32.05948318048776 1990 31.823286447509798 1991 31.58709173557804 1992 31.305735105733383 1993 31.01975677429772 1994 30.67036230761282 1995 30.243502526158963 1996 29.74963515993947 1997 29.165213916650906 1998 28.577513498414437 1999 28.01313950185067 2000 27.41605335588106 2001 26.765227931034715 2002 26.047474727242086 2003 25.337537649082613 2004 24.65631432158746 2005 23.973270222157783 2006 23.400491052169386 2007 22.99165386026772 2008 22.676430805433768 2009 22.425803994599114 2010 22.212556484406708 2011 22.036749235191266 2012 21.92043470041002 2013 21.839112928703173 2014 21.774584438799973 2015 21.69677079974097 2016 21.6139692605786 2017 21.562727081907713 2018 21.474403820853972 2019 21.319973158817973 2020 21.10514560402272 2021 20.82717881989285 2022 20.52164249065871 2023 20.16734498873048