Year % of total population 1960 16.794271655495546 1961 17.184021827180302 1962 17.578635803636697 1963 17.891959492556513 1964 18.14932736645867 1965 18.40579718290965 1966 18.667878752369326 1967 18.935181143373995 1968 19.208440309712387 1969 19.485956148011095 1970 19.77265859987055 1971 20.068607123602415 1972 20.374079952491954 1973 20.685243517428837 1974 21.008828811178734 1975 21.369937118849343 1976 21.743334005535605 1977 22.12584416648405 1978 22.521956591696988 1979 22.930808369590874 1980 23.354623889712748 1981 23.790071644740166 1982 24.242287089563302 1983 24.496192703100647 1984 24.609366817766062 1985 24.725384742310908 1986 24.84684032701039 1987 24.97535299283325 1988 25.11790621826663 1989 25.273920110164504 1990 25.447861052760917 1991 25.57225017239396 1992 25.682233694715023 1993 25.823993164720306 1994 25.986353828968316 1995 26.16111339499621 1996 26.348346243352882 1997 26.54604608437318 1998 26.756492970765738 1999 26.975891001370766 2000 27.201687687655816 2001 27.425886423758133 2002 27.49536000962159 2003 27.458954029957034 2004 27.425700942762006 2005 27.395444535560316 2006 27.366744994543176 2007 27.338893553005633 2008 27.31550286590893 2009 27.296851893328565 2010 27.28487813371751 2011 27.30794905907232 2012 27.363678736141317 2013 27.43742299889671 2014 27.525527331317456 2015 27.61500409177581 2016 27.701733346675113 2017 27.770740561865694 2018 27.74614484811414 2019 27.640555035995696 2020 27.676917911862773 2021 27.776070631901124 2022 27.890956057996778 2023 28.0336740902551