Year % of total population 1960 39.67669345571347 1961 39.491815399758245 1962 39.51905334124299 1963 39.91181902749822 1964 40.25979550441442 1965 40.39465227093961 1966 40.43173786692566 1967 40.295363140519484 1968 40.153532491590724 1969 40.07532373391905 1970 39.93773340849027 1971 39.7948842162059 1972 39.57837169751453 1973 39.349564387714466 1974 39.26453260579284 1975 39.198573423267774 1976 39.090152501364734 1977 38.654224539159706 1978 37.71122170128504 1979 36.71805058165544 1980 35.87196168602987 1981 35.10959639965173 1982 34.48326173955658 1983 33.77077192274055 1984 32.94672633077716 1985 32.172761315638795 1986 31.485430413503032 1987 30.93784826180763 1988 30.45181638819859 1989 30.039519176345337 1990 29.78443825462719 1991 29.54899121332331 1992 29.26153251034947 1993 28.969719794968075 1994 28.62437811497961 1995 28.214631814955283 1996 27.74704512511643 1997 27.198476929830168 1998 26.651516173356807 1999 26.136159367153308 2000 25.596283051836195 2001 25.001873488752462 2002 24.326173717278003 2003 23.653509746118097 2004 23.006542820769262 2005 22.339764053724405 2006 21.78759978220087 2007 21.410987710420915 2008 21.114707531559354 2009 20.874215063962605 2010 20.670855617456276 2011 20.500253010240222 2012 20.39041947955382 2013 20.319353418908157 2014 20.25957856979743 2015 20.17902689806039 2016 20.097692958542297 2017 20.057686776449213 2018 19.975324338811532 2019 19.823420392651293 2020 19.60892090068388 2021 19.327292671421677 2022 19.001508347290162 2023 18.64283046881551