Year % (national estimate) 1978 34.55 1983 54.41 1986 53.86 1987 54.6 1988 55.82 1989 59.17 1990 57.27 2009 60.25 2010 59.48 2011 60 2012 58.5 2013 58.92 2014 56.06 2015 57.693 2016 60.039 2017 58.825 2018 58.28 2019 57.055