Year % of total population 1960 40.5643898393559 1961 40.3161132775944 1962 40.0574078635921 1963 39.8952419797892 1964 39.8387109810705 1965 39.896474648053 1966 40.0635419201752 1967 40.2295652302102 1968 40.3897508764664 1969 40.5411057513658 1970 40.6901097209885 1971 40.838922860478 1972 40.9881912771814 1973 41.1366603042151 1974 41.2790365051307 1975 41.4150245763542 1976 41.5438359437437 1977 41.6629692311371 1978 41.7680509416625 1979 41.8632877642462 1980 41.9527642486891 1981 42.0343597555997 1982 42.1063045990398 1983 42.1584622165501 1984 42.1863601076218 1985 42.1924016775088 1986 42.1779603546425 1987 42.1420317260216 1988 42.0835062059293 1989 42.0013266961774 1990 41.9186773201156 1991 41.8207359391238 1992 41.6606831469894 1993 41.4311167771937 1994 41.1536864076338 1995 40.8147500834066 1996 40.4128232129103 1997 39.9383760160186 1998 39.3860637090152 1999 38.7752850312615 2000 38.0888681504137 2001 37.2863598537218 2002 36.3758545379357 2003 35.368098111174 2004 34.2703975901205 2005 33.257854770602 2006 32.4553162636398 2007 31.7256773816833 2008 30.9937700891789 2009 30.29372453605 2010 29.6389241073738 2011 29.0361200032804 2012 28.5000045067188 2013 28.021638426179 2014 27.5487976620036 2015 27.0265743184882 2016 26.4602143481627 2017 25.8207179666231 2018 25.0857338932799 2019 24.3031875318421 2020 23.5262897634452 2021 22.8027110438574 2022 22.1431264417762 2023 21.5352075024336