Year % of total population 1960 3.65234389353087 1961 3.73262499090314 1962 3.85069044879171 1963 3.96812408837027 1964 4.08496732026144 1965 4.19492677350323 1966 4.29740791268759 1967 4.39753140122886 1968 4.49366792215525 1969 4.58588342021707 1970 4.62665790185994 1971 4.63673541514149 1972 4.66134718871776 1973 4.68886409933068 1974 4.71023530389956 1975 4.70957431352608 1976 4.68732260042235 1977 4.64678457125771 1978 4.60292363895379 1979 4.58020890888521 1980 4.59932105750437 1981 4.66622970656449 1982 4.68535590970113 1983 4.63665190770535 1984 4.59247633903366 1985 4.54941983171837 1986 4.49817145636503 1987 4.44404623241645 1988 4.39950049339376 1989 4.35908024641426 1990 4.32513731583889 1991 4.32306392382438 1992 4.34109575958233 1993 4.35786615905509 1994 4.37145087474936 1995 4.37754082223074 1996 4.37662697313764 1997 4.36377637008194 1998 4.33795099059658 1999 4.30546936703148 2000 4.26577878904904 2001 4.20694936345362 2002 4.14604765702426 2003 4.10083148252326 2004 4.06158646011021 2005 4.01749128682803 2006 3.96350569770915 2007 3.90239307130934 2008 3.83296887706282 2009 3.75741040150903 2010 3.6826371140643 2011 3.60800776158392 2012 3.55483363125874 2013 3.53122725888613 2014 3.52359782680243 2015 3.53588715391289 2016 3.56956983861312 2017 3.62436399381839 2018 3.69657998334469 2019 3.77424871504527 2020 3.78863067768625 2021 3.76007081787927 2022 3.76023344232879 2023 3.77713705303519