Year % of total population 1960 30.8150597901274 1961 30.911909245413 1962 30.7465032189344 1963 30.5746264158692 1964 30.5411358051448 1965 30.5807501496956 1966 30.2536787919678 1967 29.7187676522059 1968 29.2800311264602 1969 28.7856045443276 1970 28.2838049773687 1971 27.7492804778041 1972 27.1327432942735 1973 26.455187421058 1974 25.7839546545484 1975 25.1122781429568 1976 24.4399205810557 1977 23.829136533117 1978 23.2887109682701 1979 22.8255647208831 1980 22.4725799744266 1981 22.2273317653635 1982 22.0509827661445 1983 21.883597325446 1984 21.7107495589798 1985 21.5316995876208 1986 21.3752888828725 1987 21.3186733449385 1988 21.359014985376 1989 21.4428375710267 1990 21.556647253275 1991 21.6838553496237 1992 21.7920071457062 1993 21.8585925811232 1994 21.8608729639584 1995 21.8024990164564 1996 21.720343783201 1997 21.648405466966 1998 21.5896705355766 1999 21.5255083007688 2000 21.4254043241312 2001 21.2853478322796 2002 21.1399362675084 2003 20.9923988119116 2004 20.815553884976 2005 20.6109221090081 2006 20.4194910439258 2007 20.2652113320978 2008 20.1357098160385 2009 20.0067943540569 2010 19.8668858175649 2011 19.7438057892103 2012 19.6422329152387 2013 19.5369619001623 2014 19.4233952283111 2015 19.2971595367802 2016 19.1742051083628 2017 19.0559237747833 2018 18.9110216801249 2019 18.7358999565657 2020 18.5113495341764 2021 18.2430347046008 2022 17.9594381099047 2023 17.6748321751787