Year % of total population 1960 24.0321301104504 1961 23.9999013740744 1962 24.1007818586196 1963 24.1048393271189 1964 24.0893790736362 1965 24.1186365656075 1966 24.1489830205064 1967 24.0893094335772 1968 23.9654270027837 1969 23.8173027990651 1970 23.7666485958209 1971 23.7326488467112 1972 23.508297912541 1973 23.1854873071727 1974 22.835987161455 1975 22.4338590947763 1976 21.952882340569 1977 21.4271618119657 1978 20.8788102700832 1979 20.2984786277368 1980 19.7428104229185 1981 19.2366964275526 1982 18.765654944678 1983 18.3442450381235 1984 17.9691415680805 1985 17.6398306970947 1986 17.3677041138287 1987 17.1685713969198 1988 17.0670203321233 1989 17.0387171932264 1990 17.0977054522607 1991 17.2048989661084 1992 17.3448414481858 1993 17.508813643822 1994 17.605812741475 1995 17.6506262807608 1996 17.6657720966871 1997 17.6331161398039 1998 17.5595131327515 1999 17.4790181873296 2000 17.3796260932972 2001 17.1084794134546 2002 16.8111916750956 2003 16.6123246405644 2004 16.3877761070055 2005 16.148712087318 2006 15.8962061589215 2007 15.6442988401868 2008 15.427906395523 2009 15.2651690724755 2010 15.1643116776099 2011 15.0795817763206 2012 14.9810874243253 2013 14.9186417975347 2014 14.8864754852682 2015 14.8657853212347 2016 14.8833713249582 2017 14.9357400481111 2018 14.9947371721949 2019 15.0388162864858 2020 15.0597381778765 2021 15.0657088700201 2022 15.0464929125109 2023 15.0032699877647