Year % of total population 1960 38.3438377074204 1961 38.601554225327 1962 38.8069408074588 1963 38.9703708249418 1964 39.1086559364209 1965 39.229036902646 1966 39.3478874323388 1967 39.4530938123752 1968 39.5235671876893 1969 39.5361370687312 1970 39.6433655908165 1971 39.8566401105426 1972 40.0393824566048 1973 40.1692865779927 1974 40.2135677914215 1975 40.1645674796212 1976 39.9938154443283 1977 39.7470190869112 1978 39.4710936101665 1979 39.1364262746899 1980 38.7462230566828 1981 38.3126370828438 1982 37.8345298650365 1983 37.3095005564514 1984 36.7290891170588 1985 36.0621657837723 1986 35.3698163971081 1987 34.7197172029833 1988 34.0890048030966 1989 33.4518195967232 1990 32.8388730932395 1991 32.3152863876117 1992 31.8765183544729 1993 31.4966820769255 1994 31.1642186987873 1995 30.8563802885314 1996 30.5699558029458 1997 30.406724850183 1998 30.3150087424091 1999 30.1810536206118 2000 30.0268126768892 2001 29.8048777249968 2002 29.4821797884969 2003 29.0948060055095 2004 28.6730120951437 2005 28.2148174303762 2006 27.6809650110225 2007 27.1373116731564 2008 26.6589351441165 2009 26.2039525014933 2010 25.7699582865547 2011 25.3817542766055 2012 25.0353387823555 2013 24.7186539529549 2014 24.4182216073092 2015 24.1082280448854 2016 23.7896369131006 2017 23.4919473814703 2018 23.219250210615 2019 22.9733612732765 2020 22.7323037817341 2021 22.4824530924253 2022 22.2136192212119 2023 21.9377045711302