Year % of total population 1960 29.9684076116343 1961 29.6572877654361 1962 29.1141769265489 1963 28.7174148378951 1964 28.4498155568955 1965 28.2420078574974 1966 28.0432866516502 1967 27.8272416553212 1968 27.614684597346 1969 27.4493130499491 1970 27.2934312387401 1971 27.0802304623017 1972 26.7912242081152 1973 26.4027320027807 1974 25.9107017335308 1975 25.3674545575833 1976 24.7873082433011 1977 24.1727304453939 1978 23.5499958134424 1979 22.9130224657453 1980 22.3019794150012 1981 21.7409148476527 1982 21.1831490479843 1983 20.6148042681495 1984 20.0234802452789 1985 19.4525012359029 1986 18.9839315394955 1987 18.6287354514909 1988 18.3952371709092 1989 18.2727770117961 1990 18.2448308239232 1991 18.2798500975371 1992 18.3290392480604 1993 18.375635676043 1994 18.4144725177471 1995 18.4232185729887 1996 18.4102432288693 1997 18.4254158934427 1998 18.4788999042111 1999 18.5375241268981 2000 18.5809102193295 2001 18.5894391537888 2002 18.5584852949708 2003 18.5118175517851 2004 18.4353294360216 2005 18.301847436491 2006 18.1286754601356 2007 17.9500717838027 2008 17.7869534657249 2009 17.6408314905337 2010 17.5098424112919 2011 17.3835845127903 2012 17.23349402355 2013 17.0424616738893 2014 16.8277360477398 2015 16.5960105585861 2016 16.364505134601 2017 16.1523712344102 2018 15.9420034979088 2019 15.7489795335974 2020 15.6002582801428 2021 15.5026637276371 2022 15.4249279236512 2023 15.3400624924138