Year % of total population 1960 29.038426147632613 1961 28.925506727895343 1962 28.600435596319425 1963 28.167090066239403 1964 27.691802113498234 1965 27.162009594645795 1966 26.560321665478213 1967 25.953811083784295 1968 25.392997844047674 1969 24.8776934495984 1970 24.374669672549985 1971 23.93442310623825 1972 23.61279605386024 1973 23.4075693936902 1974 23.357876399475487 1975 23.433581579365192 1976 23.5903767493379 1977 23.750608572009654 1978 23.854580898435195 1979 23.958229048151235 1980 24.08485939267233 1981 24.211679063471998 1982 24.227752182179877 1983 24.12926221888287 1984 24.035928699041165 1985 23.963667788576153 1986 23.891970110215237 1987 23.784965672001576 1988 23.612474315091227 1989 23.35491325347203 1990 23.006535847634225 1991 22.615397477387784 1992 22.195921977504934 1993 21.742208679289007 1994 21.264410347695147 1995 20.76613025884487 1996 20.27271384206007 1997 19.784947765270456 1998 19.28275291824844 1999 18.760834769618906 2000 18.21762205468794 2001 17.678766016104337 2002 17.153750016767713 2003 16.6585147542928 2004 16.207291175191536 2005 15.823027420398601 2006 15.51636560637408 2007 15.292166233475557 2008 15.155279856374554 2009 15.088916988360065 2010 15.068015314466598 2011 15.05104295156611 2012 15.034262934058466 2013 15.025575718827639 2014 15.022849083830971 2015 15.036557955280239 2016 15.080184170951256 2017 15.165777273260826 2018 15.258864804346445 2019 15.325884944019926 2020 15.363146185825341 2021 15.378250029119137 2022 15.259005547550801 2023 15.13149855320089