Year % of total population 1960 28.3184017387358 1961 28.2607302440722 1962 28.0437115441912 1963 27.6659425916445 1964 27.1500079839342 1965 26.5336886701664 1966 25.7958347958896 1967 25.0474977809044 1968 24.4870901916817 1969 24.1145477831553 1970 23.8470421871022 1971 23.6569689515046 1972 23.6222596421838 1973 23.7940683535845 1974 24.2024732761933 1975 24.776016174031 1976 25.4521866095201 1977 25.9729544213224 1978 26.2431110455554 1979 26.4918469294532 1980 26.7537297419843 1981 27.0195771591917 1982 26.7491256406518 1983 25.9175155493975 1984 25.1952756632451 1985 24.7036418458606 1986 24.4073223908527 1987 24.2307965228362 1988 24.0903163675963 1989 23.8835585709969 1990 23.5003853962961 1991 22.9941601137267 1992 22.4109876411799 1993 21.8110290904853 1994 21.2427432675514 1995 20.6768552479207 1996 20.1504750551998 1997 19.7331370977456 1998 19.4090814043726 1999 19.0557628332401 2000 18.6141080676253 2001 18.0758056280534 2002 17.4533073865271 2003 16.8555726556841 2004 16.3343574870091 2005 15.9696326570166 2006 15.8025326549878 2007 15.7425775745834 2008 15.7446279423705 2009 15.7790790703047 2010 15.8274113801917 2011 15.854675144292 2012 15.8469076855983 2013 15.7982170922689 2014 15.7327384494636 2015 15.719361407136 2016 15.7671324418547 2017 15.8601924690742 2018 15.9500082190944 2019 16.0020755768312 2020 16.0181197048859 2021 16.0267810949186 2022 15.9188797811963 2023 15.8389372000298