Year % of population 1984 63.1 1985 60.2 1986 57.7 1987 55.1 1988 51.1 1989 57.6 1990 56.5 1991 55.2 1992 53.3 1993 51.4 1994 48 1995 45.9 1996 44.3 1997 44.4 1998 45.3 1999 43.5 2000 42.2 2001 41.1 2002 39.4 2003 37.9 2004 36.5 2005 35 2006 34.4 2007 33.6 2008 33.1 2009 32.3 2010 31.3 2011 29.8 2012 29.1 2013 26.7 2014 26.1 2015 25.1 2016 24.9 2017 24.7 2018 24 2019 23.4 2020 22.3 2021 21.9 2022 21.4