Year % of total population 1960 15.675260590500008 1961 16.073373711701826 1962 16.482946257820995 1963 16.895535041532327 1964 17.319284645957566 1965 17.756886613791657 1966 18.131267241564515 1967 18.372089742588088 1968 18.615801185600507 1969 18.86608403024876 1970 19.126942223945726 1971 19.424565363013322 1972 19.732515417907386 1973 20.045892277236103 1974 20.336323127017547 1975 20.60228875008759 1976 20.72006370055316 1977 20.805933053434938 1978 20.927775314361064 1979 21.030564182768767 1980 21.073455438703892 1981 21.04274419909771 1982 21.007101037261876 1983 20.982962297721574 1984 20.958261331862385 1985 20.961180395883147 1986 20.98532966430262 1987 20.943881192039168 1988 20.9259571938953 1989 20.88765349487358 1990 20.842046710681803 1991 20.823723958686085 1992 20.86875924867449 1993 20.966261312679485 1994 21.088223474972942 1995 21.153223843705714 1996 21.218998646859315 1997 21.26342052872406 1998 21.300608235018867 1999 21.338154879012123 2000 21.376787783952295 2001 21.416687420626012 2002 21.5132622452328 2003 21.58473998486838 2004 21.524499948211403 2005 21.469179412857518 2006 21.425936973118443 2007 21.385331009221485 2008 21.458227712777006 2009 21.530463744301965 2010 21.564299269151874 2011 21.23507044267079 2012 21.007461976953746 2013 20.818163001061983 2014 20.665574833993865 2015 20.748264497974244 2016 20.925628305702542 2017 20.983207055073375 2018 21.038515078912003 2019 21.062911966257992 2020 21.114009650536698 2021 21.191434193812885 2022 21.274978003841174 2023 21.35567344943562