Year	Percent
1991	61.121
1992	61.486
1993	61.941
1994	61.984
1995	62.063
1996	62.296
1997	62.399
1998	62.441
1999	62.314
2000	62.003
2001	61.542
2002	60.639
2003	59.83
2004	59.106
2005	58.548
2006	58.082
2007	57.712
2008	56.147
2009	54.515
2010	52.76
2011	51.187
2012	49.779
2013	49.696
2014	49.558
2015	49.33
2016	49.337
2017	49.181
2018	49.09
2019	49.041
2020	48.952
2021	48.827
2022	48.667