Year % of total population 1960 3.8176386825161 1961 3.65474748538628 1962 3.49829289155658 1963 3.34659090909091 1964 3.2009766392849 1965 3.06856909469512 1966 2.95017837532247 1967 2.85206339599803 1968 2.76099875278179 1969 2.64672582528646 1970 2.51440785580078 1971 2.38040881781381 1972 2.24788805334081 1973 2.1199326972316 1974 2.00221681234532 1975 1.90570486082179 1976 1.83405242997707 1977 1.78773363734152 1978 1.97085171814414 1979 2.77215447771222 1980 3.37983945022068 1981 3.41558645677368 1982 3.45946382755207 1983 3.50906953441216 1984 3.56117129811431 1985 3.61293278945906 1986 3.66663613884055 1987 3.72009774500557 1988 3.77000923168034 1989 3.82012623912054 1990 3.83245240501715 1991 3.80856944287307 1992 3.78710725039807 1993 3.76288850062751 1994 3.73590218510502 1995 3.70578771067601 1996 3.67313531504254 1997 3.63334470092972 1998 3.58707288298523 1999 3.53461522045328 2000 3.5335339504566 2001 3.56335343989728 2002 3.57129605121571 2003 3.58393021275364 2004 3.60415494665088 2005 3.63272948663458 2006 3.66225930536397 2007 3.68938161418383 2008 3.71613895983159 2009 3.7575853660063 2010 3.77791267574648 2011 3.76948912429266 2012 3.76175365847497 2013 3.75720733796652 2014 3.75323698629629 2015 3.74567941874956 2016 3.72875311597427 2017 3.70711723786259 2018 3.69898216604215 2019 3.70395312815678 2020 3.71336445449733 2021 3.72317174625905 2022 3.73736956391999 2023 3.75733170705458