Year % of total population 1960 25.3196571497663 1961 25.1396153791487 1962 24.8127658102077 1963 24.3411574374212 1964 23.8434114265491 1965 23.3310933838064 1966 22.8378928415 1967 22.4290233600032 1968 22.0039401277076 1969 21.4305278578085 1970 20.83196563263 1971 20.3691131424127 1972 20.1062831942241 1973 20.0131002246432 1974 20.1156928793003 1975 20.4144697697623 1976 20.7634658515423 1977 21.1288694792093 1978 21.4676805006947 1979 21.7419860971692 1980 21.9434894719245 1981 22.0629888527071 1982 22.0708978624388 1983 21.9565058967507 1984 21.7938226748341 1985 21.6511159393876 1986 21.5347525150936 1987 21.3876905979138 1988 21.1807194286939 1989 20.7978563402694 1990 20.2339641920416 1991 19.7009237912018 1992 19.2515897086618 1993 18.8475064809814 1994 18.488989148976 1995 18.1777252711888 1996 17.8885297650648 1997 17.6107889973187 1998 17.3575559378349 1999 17.1059746696466 2000 16.8202827763622 2001 16.4978819419029 2002 16.2284474062245 2003 16.0102547305996 2004 15.7801642826521 2005 15.5515663309732 2006 15.3282730419543 2007 15.1302614440954 2008 14.9721804038705 2009 14.8349373654873 2010 14.6900241067607 2011 14.5559219408304 2012 14.468838183587 2013 14.4358670166811 2014 14.4563367630056 2015 14.4841463734246 2016 14.5051486716214 2017 14.5309947214923 2018 14.5441489839135 2019 14.5483703583441 2020 14.5570170366919 2021 14.553461837367 2022 14.4414928505015 2023 14.3803084980572