Year % of total population 1960 40.8701864063838 1961 41.5564251751068 1962 42.1739214221416 1963 42.8315068258328 1964 43.1696152686698 1965 43.2250806509579 1966 43.3153916267521 1967 43.2750125475516 1968 43.1218270169774 1969 42.920272436044 1970 42.6605812940463 1971 42.4332410210085 1972 42.1364278095903 1973 41.8059027786943 1974 41.4611645570117 1975 41.0682908286923 1976 40.8126901132035 1977 40.5595039474363 1978 40.1768199644278 1979 39.9317172450435 1980 39.7997182067653 1981 39.7253490827646 1982 39.7309376108453 1983 39.7330986763544 1984 39.6976478629091 1985 39.6297959582513 1986 39.5071111707674 1987 39.3040236002142 1988 39.010680520796 1989 38.6751078059395 1990 38.3297226787422 1991 37.9550751461187 1992 37.5421388670143 1993 37.0668015821619 1994 36.5061409355145 1995 35.8396763746222 1996 35.0530379034572 1997 34.1744825368407 1998 33.2380766216491 1999 32.2919672782836 2000 31.3737065978109 2001 30.4890815894878 2002 29.658110727684 2003 28.8731481324255 2004 28.1156398513877 2005 27.3728039170339 2006 26.6283097763937 2007 25.9139424754778 2008 25.2732199627789 2009 24.7254017115344 2010 24.2880828333162 2011 23.9677461856679 2012 23.7488126646004 2013 23.6084251739618 2014 23.5120771816643 2015 23.4192224930748 2016 23.3101999501678 2017 23.1720862648204 2018 23.0177243888372 2019 22.8589111216817 2020 22.693134535111 2021 22.5451502797145 2022 22.3901369242335 2023 22.197378689537