Year % of total population 1960 69.49 1961 68.203 1962 66.786 1963 65.338 1964 63.859 1965 62.357 1966 61.16 1967 60.996 1968 60.831 1969 60.666 1970 60.5 1971 60.335 1972 60.169 1973 60.003 1974 59.837 1975 59.67 1976 59.503 1977 59.072 1978 58.206 1979 57.335 1980 56.458 1981 55.58 1982 54.697 1983 53.811 1984 52.921 1985 52.032 1986 51.14 1987 50.278 1988 49.489 1989 48.702 1990 47.915 1991 47.129 1992 46.343 1993 45.561 1994 44.781 1995 44.003 1996 43.226 1997 42.456 1998 41.687 1999 40.882 2000 40.081 2001 39.288 2002 38.499 2003 37.716 2004 36.939 2005 36.17 2006 35.407 2007 34.652 2008 33.903000000000006 2009 33.17400000000001 2010 32.459999999999994 2011 31.763999999999996 2012 31.084999999999994 2013 30.424000000000007 2014 29.778999999999996 2015 29.152 2016 28.540999999999997 2017 27.947999999999993 2018 27.370999999999995 2019 26.811000000000007 2020 26.266999999999996 2021 25.739000000000004 2022 25.227999999999994 2023 24.732