Year % of total population 1960 17.261937355384134 1961 17.61444063883362 1962 18.03708344274985 1963 18.47474930630951 1964 18.92517947220581 1965 19.383968925732464 1966 19.86014170526196 1967 20.352829030448436 1968 20.8630464145015 1969 21.38552153936142 1970 21.975294732757273 1971 22.594696882569025 1972 23.169253780863265 1973 23.40549452683634 1974 23.661330893743347 1975 23.932407589756355 1976 24.22128826567926 1977 24.506858807664628 1978 24.78799746130656 1979 25.07782757499845 1980 25.369603243830497 1981 25.668317538409923 1982 25.72758405021951 1983 25.779562504853427 1984 25.83919667508156 1985 25.908837010504588 1986 25.99265841291932 1987 26.088994628316662 1988 26.187985423054773 1989 26.288754356150353 1990 26.39880078333359 1991 26.534842172915337 1992 26.69549093236642 1993 26.863331201542984 1994 26.88783567270135 1995 26.922312539278103 1996 26.975557049450234 1997 27.036710578739076 1998 27.113109940241443 1999 27.217602277657154 2000 27.363355874794436 2001 27.5571018951054 2002 27.79945916704613 2003 28.079007532072243 2004 28.38384692630589 2005 28.710620466278307 2006 29.06433293337202 2007 29.439321922462096 2008 29.806019089303216 2009 30.16671948876027 2010 30.51621487991682 2011 30.84228933437561 2012 31.150023618813695 2013 31.44362680957158 2014 31.71666515505675 2015 31.95096630901225 2016 32.12706774425759 2017 32.25540338155218 2018 32.26501387531912 2019 32.1546281643051 2020 32.18515697878105 2021 32.27822918445956 2022 32.436830072657564 2023 32.61570648890994