Year % of total population 1960 22.0467014155716 1961 22.4331620029795 1962 22.6667271709913 1963 22.8413207630664 1964 23.0855249909645 1965 23.3587092400873 1966 23.6234112040799 1967 23.869372776927 1968 24.1006106443544 1969 24.2923634118075 1970 24.3697557787526 1971 24.3234800158778 1972 24.1674673965805 1973 23.9051242266225 1974 23.5967066342566 1975 23.2380189538607 1976 22.7551581034814 1977 22.1789994605066 1978 21.570546155292 1979 20.9615963259795 1980 20.4226358407282 1981 19.9783937137708 1982 19.5521330647925 1983 19.0961568226947 1984 18.6587661344336 1985 18.2996856632739 1986 18.0100204189145 1987 17.7811149058232 1988 17.6430874893794 1989 17.565466686607 1990 17.5231734314364 1991 17.5719650659301 1992 17.6916779011472 1993 17.7879397655554 1994 17.8317758540407 1995 17.8161363195819 1996 17.72898631711 1997 17.5786701623792 1998 17.4085885638443 1999 17.236098186589 2000 17.046335286558 2001 16.8228171822183 2002 16.6177352323161 2003 16.4354237334891 2004 16.233090874535 2005 16.0181715537962 2006 15.7715384577704 2007 15.5069151202415 2008 15.2525530932903 2009 15.0206842663473 2010 14.825031098926 2011 14.6496695734621 2012 14.4937091890024 2013 14.3772910296185 2014 14.304366143695 2015 14.3069690772991 2016 14.3689170698083 2017 14.4179718865459 2018 14.4324211973005 2019 14.4250419724143 2020 14.4032175479921 2021 14.3854932066305 2022 14.3780936028915 2023 14.3668732549943