Year % of total population 1960 40.288 1961 39.546 1962 38.807 1963 38.074 1964 37.358 1965 36.657 1966 35.959999999999994 1967 35.269999999999996 1968 34.584 1969 33.907 1970 33.236000000000004 1971 32.571 1972 31.912000000000006 1973 31.262 1974 30.619 1975 29.983000000000004 1976 29.352999999999994 1977 28.733999999999995 1978 28.120999999999995 1979 27.516000000000005 1980 26.897999999999996 1981 26.156999999999996 1982 25.429000000000002 1983 24.715000000000003 1984 24.013000000000005 1985 23.325999999999993 1986 22.653000000000006 1987 21.992999999999995 1988 21.346000000000004 1989 20.715999999999994 1990 20.162000000000006 1991 19.933000000000007 1992 19.706999999999994 1993 19.482 1994 19.260000000000005 1995 19.039 1996 18.819999999999993 1997 18.604 1998 18.388999999999996 1999 18.176000000000002 2000 17.992999999999995 2001 17.950999999999993 2002 17.908 2003 17.866 2004 17.823999999999998 2005 17.781999999999996 2006 17.739999999999995 2007 17.697999999999993 2008 17.656999999999996 2009 17.614999999999995 2010 17.572999999999993 2011 17.524 2012 17.468000000000004 2013 17.403999999999996 2014 17.331999999999994 2015 17.254000000000005 2016 17.168000000000006 2017 17.075000000000003 2018 16.974999999999994 2019 16.867999999999995 2020 16.754999999999995 2021 16.635000000000005 2022 16.507999999999996 2023 16.375