Year % of total population 1960 35.8786734332586 1961 36.5659961741348 1962 37.2712808273667 1963 37.9264288496856 1964 38.4560867906013 1965 38.7539373231541 1966 38.9275074478649 1967 38.9949337290824 1968 38.9389840697325 1969 38.7781160986151 1970 38.3669594113458 1971 37.6630385895475 1972 36.814399728307 1973 35.9117576147231 1974 34.9100472633023 1975 33.8662896091654 1976 32.8110407803258 1977 31.7124805663061 1978 30.5845743498555 1979 29.4336742482064 1980 28.5730994152047 1981 27.9741957104558 1982 27.321995888619 1983 26.653552359298 1984 25.9940783517263 1985 25.3560117302053 1986 24.7212272757992 1987 24.067693774513 1988 23.4580785205903 1989 22.9307296689167 1990 22.4378061665546 1991 21.95278067336 1992 21.515875368333 1993 21.1545183680943 1994 20.8546192408689 1995 20.60697518444 1996 20.3883779080819 1997 20.1734169032294 1998 19.9382891478218 1999 19.7166731949341 2000 19.6590894764048 2001 19.6714123908463 2002 19.6071272949961 2003 19.5018523795953 2004 19.3523456217637 2005 19.1732742662087 2006 18.9748220105029 2007 18.7725340906802 2008 18.5767658392504 2009 18.3949126926038 2010 18.274200856242 2011 18.2035248324083 2012 18.083890256771 2013 17.895794681509 2014 17.6957496285227 2015 17.5042274794372 2016 17.3465371981142 2017 17.2402132712603 2018 17.1529190555453 2019 17.0479632261772 2020 16.8896383179444 2021 16.7848127274862 2022 16.7643056232762 2023 16.7169239647958