Year % of total population 1960 39.2881564668801 1961 40.6140775572195 1962 41.8252427749957 1963 42.8706695106415 1964 43.6186225632228 1965 44.0812400011597 1966 44.4149263597433 1967 44.6328823064338 1968 44.7291578415376 1969 44.717317650336 1970 44.6056021716773 1971 44.4025306102982 1972 44.1073564872646 1973 43.7284596085736 1974 43.2891633454634 1975 42.8128082611158 1976 42.3268787181321 1977 41.8535636363568 1978 41.4048461538179 1979 41.0023466638992 1980 40.6542518810012 1981 40.3786857083531 1982 40.1952280002562 1983 40.0869994752129 1984 40.0358456943265 1985 40.0410608684565 1986 40.1137925944906 1987 40.2303249919363 1988 40.3197404222479 1989 40.3971801866372 1990 40.4255756659078 1991 40.3408724439113 1992 40.2025713575862 1993 40.0363147194662 1994 39.8159924307467 1995 39.5406805858956 1996 39.2855025455158 1997 38.9873323444874 1998 38.5331209907216 1999 37.944619729556 2000 37.2347964558695 2001 36.4145365768202 2002 35.525243465667 2003 34.6526545825136 2004 33.7760322437151 2005 32.9242443624604 2006 32.1818867027222 2007 31.518217100699 2008 30.9366564168325 2009 30.4798128994315 2010 30.174757086198 2011 30.0201191554674 2012 29.9981479045674 2013 30.0785984842524 2014 30.2310003333832 2015 30.4216914741812 2016 30.6310669147797 2017 30.8462359067774 2018 31.0338997135398 2019 31.1680593398956 2020 31.2326832135604 2021 31.2166944845002 2022 31.1197312981392 2023 30.9338024278326