Year % of total population 1960 2.83302943728627 1961 2.81767412123129 1962 2.79905450373125 1963 2.77896791191492 1964 2.75892911923386 1965 2.73924697654934 1966 2.72152713232255 1967 2.70620567570727 1968 2.69199781279447 1969 2.67791015465783 1970 2.663022030701 1971 2.64957597034893 1972 2.63657327473071 1973 2.62251416366628 1974 2.61002671594322 1975 2.59985164574029 1976 2.5926484077707 1977 2.58448969625259 1978 2.57072830011139 1979 2.55017780566685 1980 2.52454795354536 1981 2.49797067644268 1982 2.46483335602466 1983 2.4281891009038 1984 2.38211604777245 1985 2.3269724672373 1986 2.2876186845665 1987 2.26533451622134 1988 2.2521684608102 1989 2.24954286067909 1990 2.24657394119533 1991 2.24616332161241 1992 2.25392088017408 1993 2.26506666780922 1994 2.27406917040731 1995 2.27980392367046 1996 2.28429438224573 1997 2.28646994496937 1998 2.28587834662079 1999 2.28535007609856 2000 2.28480734708738 2001 2.28484634471185 2002 2.28883394829011 2003 2.29391264258585 2004 2.29664737806727 2005 2.29941264028069 2006 2.30238096660512 2007 2.30571196902109 2008 2.31761413685953 2009 2.33529238260334 2010 2.35343107220261 2011 2.37388209171293 2012 2.39198468572599 2013 2.403284579283 2014 2.40916200256692 2015 2.40581576446341 2016 2.39898955450016 2017 2.39981758202619 2018 2.4070929738622 2019 2.41775383911968 2020 2.41695301478831 2021 2.40405843848977 2022 2.3943397190254 2023 2.39513967070057