Year % of total population 1960 27.2575584328548 1961 27.2873358353619 1962 27.1193439534419 1963 26.8713956548457 1964 26.5669913084143 1965 26.1711770262475 1966 25.7568026680843 1967 25.3784224211975 1968 24.9936714693507 1969 24.6259186756835 1970 24.2920966767962 1971 24.0223411160073 1972 23.8398166478736 1973 23.7148723561754 1974 23.6084262205968 1975 23.5025064053192 1976 23.3956125914725 1977 23.2859499915963 1978 23.1888446825322 1979 23.1123336546224 1980 23.0167501108952 1981 22.8862671386478 1982 22.7496633740604 1983 22.6226988125076 1984 22.4952586984697 1985 22.3385648685441 1986 22.1259217677528 1987 21.8637220028528 1988 21.5724298053173 1989 21.2353422416144 1990 20.8366062041546 1991 20.3992868621053 1992 19.9451374451374 1993 19.4664114722989 1994 18.9570759783454 1995 18.4204909231352 1996 17.8820761790084 1997 17.3748183260061 1998 16.9001181423734 1999 16.444414908212 2000 16.0219347601393 2001 15.6266094052571 2002 15.2286785696102 2003 14.8538902082349 2004 14.5503015818681 2005 14.3187638933678 2006 14.1487294081481 2007 14.0624219996847 2008 14.0657501623622 2009 14.116596873842 2010 14.1970920447434 2011 14.3140512032954 2012 14.4591258914618 2013 14.608990797754 2014 14.7542769180647 2015 14.8706641766729 2016 14.9596176113147 2017 15.0486181800159 2018 15.1325024074943 2019 15.1861788161919 2020 15.2025532184162 2021 15.1884286637386 2022 15.1165840505245 2023 14.9618255066993