Year % of total population 1960 37.6980223503223 1961 38.0019979163362 1962 38.6296058855063 1963 39.2864905509637 1964 40.4197937103765 1965 41.8071525765272 1966 42.6810934200364 1967 42.8120094875999 1968 42.4818051174473 1969 42.4606573285852 1970 42.4153127838928 1971 42.3670083254626 1972 42.3402970047823 1973 41.9580970253795 1974 41.7766573574491 1975 42.0584550103807 1976 42.7757711664213 1977 43.7617241626411 1978 44.7892779876336 1979 45.1519811684174 1980 45.2253108227972 1981 45.6061077664307 1982 45.980949874189 1983 46.3211310937884 1984 46.6041607543137 1985 46.81997760219 1986 46.9690331438073 1987 47.0593209020172 1988 47.0984153509858 1989 47.0912267190127 1990 47.0237548026528 1991 46.8689864874723 1992 46.6628605114163 1993 46.4744156909651 1994 46.2771781277275 1995 46.0211130822701 1996 45.7251834443929 1997 45.4199239962407 1998 45.1396917921307 1999 44.8828155434763 2000 44.6252952230534 2001 44.3829232213014 2002 44.1839030394481 2003 44.0342384982064 2004 43.9180064869648 2005 43.850693532167 2006 43.8276801748685 2007 43.8076001027181 2008 43.7606634903924 2009 43.6718154290004 2010 43.5529333619615 2011 43.4267630484948 2012 43.2935453276195 2013 43.1456587459008 2014 42.9733053635357 2015 42.7595659725231 2016 42.5011235716195 2017 42.1793447427196 2018 41.800754251594 2019 41.3967778532538 2020 40.9832336885885 2021 40.5620896763803 2022 40.113736665993 2023 39.6386624401049