Year % of total population 1960 30.4609759569657 1961 30.8294674433819 1962 30.7703194863227 1963 30.5666512849688 1964 30.1150358702095 1965 29.5127625455153 1966 28.8931712256534 1967 28.2330778673879 1968 27.5857234053591 1969 26.9022185123191 1970 26.1480470780098 1971 25.4491574773418 1972 24.8302245531 1973 24.2101376097673 1974 23.6053004787135 1975 23.0443997589498 1976 22.539033241052 1977 22.1220642584193 1978 21.8027373925944 1979 21.638268589739 1980 21.6404385384886 1981 21.7357547618285 1982 21.9148354026031 1983 22.187767268978 1984 22.4728258551331 1985 22.6907082346393 1986 22.8581417212258 1987 22.9947005381389 1988 23.1038745240289 1989 23.1050940512975 1990 22.980548178672 1991 22.7966558697428 1992 22.5290561190237 1993 22.2029987520926 1994 21.8727145138599 1995 21.5109095352245 1996 21.0832596977749 1997 20.5464818527882 1998 19.8547987145778 1999 19.0861252791338 2000 18.320430382984 2001 17.5126129829303 2002 16.6637662297954 2003 15.9992727672749 2004 15.5697736786839 2005 15.2085851681157 2006 14.9362071305406 2007 14.8202549631652 2008 14.8747283715676 2009 15.0260237510162 2010 15.1605885062166 2011 15.3603646452539 2012 15.6987743912697 2013 16.0741100045898 2014 16.4601039456127 2015 16.8510270863284 2016 17.2113708069139 2017 17.4741102485831 2018 17.6066010083569 2019 17.6608351756578 2020 17.6804678846996 2021 17.719607735911 2022 17.7042504188661 2023 17.5729822027872