Year % of total population 1960 37.2856604947367 1961 37.8267070752863 1962 38.4129162419469 1963 39.0135174342559 1964 39.5760578425005 1965 40.1152109606103 1966 40.9549864845388 1967 42.0377710797313 1968 43.0283637025651 1969 43.9085411439019 1970 44.6599716487333 1971 45.0447985057072 1972 45.0787411268837 1973 45.019584730556 1974 44.8828445710803 1975 44.640389562577 1976 44.099134960457 1977 43.3664735713284 1978 42.7099243533468 1979 42.1514431417311 1980 41.7231419065916 1981 41.1953962631907 1982 40.5445874303733 1983 39.9517749713714 1984 39.598541554345 1985 39.3249513625114 1986 39.3166788061644 1987 39.5931709264981 1988 39.6687321202375 1989 39.5054463480532 1990 38.8414194559498 1991 37.2523329600597 1992 36.222420498657 1993 34.4661140892132 1994 32.9104884145205 1995 32.3593247187763 1996 31.9563733713767 1997 31.3003894193964 1998 30.4926315349803 1999 29.6013107300577 2000 28.6814858534142 2001 27.7822073291111 2002 26.9425221895081 2003 26.1781788869506 2004 25.4761768216615 2005 24.8888734802793 2006 24.4529829580915 2007 24.0884181988847 2008 23.7330062029163 2009 23.3561195471374 2010 23.0246319125801 2011 22.6986271021172 2012 22.3287554611459 2013 21.9584134782826 2014 21.8591585166194 2015 21.7090251264921 2016 21.5923208134217 2017 21.5064009360702 2018 21.1430572070623 2019 20.8345590996104 2020 20.9743066331884 2021 21.1201276012832 2022 20.7151278569309 2023 20.1268065819704