Year % of total population 1960 44.71 1961 43.679 1962 42.838 1963 42.002 1964 41.168 1965 40.342 1966 39.52 1967 38.705 1968 37.894 1969 37.092 1970 36.296 1971 35.477000000000004 1972 34.634 1973 33.803 1974 32.980999999999995 1975 32.169 1976 31.366 1977 30.576999999999998 1978 29.798000000000002 1979 29.03 1980 28.272999999999996 1981 27.471999999999994 1982 26.626999999999995 1983 25.798000000000002 1984 24.985 1985 24.191999999999993 1986 23.433000000000007 1987 22.709000000000003 1988 22 1989 21.308999999999997 1990 20.632999999999996 1991 20.156999999999996 1992 19.872 1993 19.590999999999994 1994 19.311999999999998 1995 19.037000000000006 1996 18.777 1997 18.534000000000006 1998 18.293000000000006 1999 18.054000000000002 2000 17.816999999999993 2001 17.632000000000005 2002 17.497 2003 17.361999999999995 2004 17.227999999999994 2005 17.095 2006 16.962999999999994 2007 16.831999999999994 2008 16.700999999999993 2009 16.570999999999998 2010 16.230000000000004 2011 15.686999999999998 2012 15.159000000000006 2013 14.875 2014 14.825000000000003 2015 14.775000000000006 2016 14.724999999999994 2017 14.674999999999997 2018 14.617999999999995 2019 14.554000000000002 2020 14.483000000000004 2021 14.403999999999996 2022 14.319000000000003 2023 14.227000000000004