Year % of total population 1960 25.9249145614153 1961 25.6006033249354 1962 25.2490462358691 1963 24.9939320388349 1964 24.8397997820376 1965 24.7507291841933 1966 24.7004024564914 1967 24.652238090532 1968 24.5886327535219 1969 24.5484332052292 1970 24.4869852548537 1971 24.385416985606 1972 24.2830939981139 1973 24.1591058369719 1974 23.991250520653 1975 23.7951583625216 1976 23.5525624122414 1977 23.2552077343576 1978 22.9286367802949 1979 22.5671598546647 1980 22.1702927424313 1981 21.7532719758713 1982 21.3300052904897 1983 20.8885446213055 1984 20.4241642776117 1985 20.0075614594339 1986 19.6368315037015 1987 19.2961321564945 1988 19.0630201586687 1989 18.9526963568653 1990 18.9404063597638 1991 19.0029931580768 1992 19.1153062936058 1993 19.2527090982288 1994 19.3733794709136 1995 19.4827075016645 1996 19.6005600808854 1997 19.7110389031841 1998 19.8057032831036 1999 19.9148391159628 2000 20.0089998188681 2001 20.0362448790069 2002 20.0155119465675 2003 19.9448651117401 2004 19.8163024573648 2005 19.6415892158837 2006 19.4477576316686 2007 19.2535889373492 2008 19.0810866127004 2009 18.9490618476209 2010 18.811487152387 2011 18.6281444803042 2012 18.4415854296107 2013 18.2894534449551 2014 18.1343202171072 2015 17.9809421568634 2016 17.8728636262208 2017 17.7818022820929 2018 17.6388658815734 2019 17.4377979755542 2020 17.2111656129486 2021 16.966313845532 2022 16.707318801123 2023 16.4339027758496