Year % of total population 1960 3.33550078685131 1961 3.32940859574842 1962 3.31886134485166 1963 3.30496123559724 1964 3.28885376913585 1965 3.27068007735743 1966 3.25100955567782 1967 3.23012392879836 1968 3.20685338077163 1969 3.17987313456433 1970 3.15836198472069 1971 3.14696416821869 1972 3.14026707614885 1973 3.1358488871703 1974 3.13185474353016 1975 3.13560625102252 1976 3.14933702394589 1977 3.19144732315478 1978 3.30736713735725 1979 3.4577565272446 1980 3.41004997782955 1981 3.28901145483277 1982 3.25038694014773 1983 3.2156433790966 1984 3.18799028453306 1985 3.15773557966728 1986 3.12523794829459 1987 3.09611809273598 1988 3.08259531376078 1989 3.08492104583771 1990 3.09444642137306 1991 3.10377473485507 1992 3.11651993454683 1993 3.163025416219 1994 3.22501697733611 1995 3.24963754229962 1996 3.24044962275134 1997 3.21346240053214 1998 3.17183022634202 1999 3.1227919674847 2000 3.07569032410814 2001 3.02990665543613 2002 2.98291296762757 2003 2.94059740911359 2004 2.91391294290632 2005 2.90607110450702 2006 2.89687190046787 2007 2.89207689159242 2008 2.90259293617169 2009 2.91806422966906 2010 2.94034850545031 2011 2.96831630492903 2012 2.98909616352581 2013 2.99456567986469 2014 3.02818619818064 2015 3.09762593786182 2016 3.16741409886295 2017 3.23311798895554 2018 3.29335928925663 2019 3.34578073715007 2020 3.37626213602766 2021 3.36334256290234 2022 3.32184535349542 2023 3.29571879381174