Year % of total population 1960 38.4454165848007 1961 39.3250578780403 1962 39.9424729901485 1963 40.4205533577481 1964 40.7854164803532 1965 40.9107907831508 1966 40.8339641018996 1967 40.6887369023809 1968 40.4881945882129 1969 40.2828301386082 1970 40.1072277269738 1971 39.9760624319229 1972 39.8592870960019 1973 39.6814506438434 1974 39.4267778923144 1975 39.1281363209446 1976 38.8217627444874 1977 38.509695077623 1978 38.1942529354052 1979 37.9043067673194 1980 37.6386165074912 1981 37.4367662127997 1982 37.3293183643306 1983 37.2933291027883 1984 37.2702660009753 1985 37.2497494680925 1986 37.2802556532392 1987 37.3521552935454 1988 37.4392865664701 1989 37.5462053972471 1990 37.7170950505764 1991 37.8838507446207 1992 38.0803861674716 1993 38.4006929578458 1994 38.5400498731542 1995 38.4376571863192 1996 38.2164580737306 1997 37.8038112555626 1998 37.2544531793174 1999 36.6003192105779 2000 35.8911687552759 2001 35.1391283330697 2002 34.3378575933852 2003 33.5355804277298 2004 32.756947580708 2005 32.0550282600217 2006 31.4687946999925 2007 31.0380979100963 2008 30.7732701764035 2009 30.6469144832414 2010 30.6682314041388 2011 30.8486401803349 2012 31.1680828870921 2013 31.5674807152998 2014 32.002492081107 2015 32.4666581741056 2016 32.9175569375998 2017 33.3257504724721 2018 33.7323347839385 2019 34.1046213393134 2020 34.3532106621858 2021 34.4645818267829 2022 34.4460693964956 2023 34.301029011495