Year % of total population 1960 89.565 1961 89.202 1962 88.79599999999999 1963 88.376 1964 87.94200000000001 1965 87.496 1966 87.035 1967 86.559 1968 86.068 1969 85.564 1970 85.043 1971 84.368 1972 83.545 1973 82.69 1974 81.798 1975 80.872 1976 79.908 1977 78.912 1978 77.878 1979 76.80799999999999 1980 75.702 1981 74.563 1982 73.388 1983 72.179 1984 70.935 1985 69.662 1986 68.357 1987 67.02199999999999 1988 65.657 1989 64.269 1990 62.856 1991 61.42 1992 59.961 1993 58.489 1994 57 1995 55.831 1996 54.654 1997 53.475 1998 52.29 1999 51.103 2000 49.913 2001 48.726 2002 47.539 2003 46.355 2004 45.173 2005 44 2006 43.236 2007 42.476 2008 41.718 2009 40.966 2010 40.217 2011 39.472 2012 38.732 2013 37.998 2014 37.269 2015 36.554 2016 35.851 2017 35.161 2018 34.486000000000004 2019 33.82299999999999 2020 33.175 2021 32.540000000000006 2022 31.918999999999997 2023 31.311999999999998