Year	Percent
1991	62.396
1992	62.361
1993	62.051
1994	62.041
1995	61.508
1996	60.876
1997	59.891
1998	59.449
1999	59.037
2000	58.077
2001	58.141
2002	58.027
2003	58.453
2004	58.458
2005	58.555
2006	56.751
2007	54.934
2008	52.518
2009	51.063
2010	49.233
2011	47.697
2012	46.015
2013	45.781
2014	45.205
2015	44.346
2016	43.404
2017	43.11
2018	42.831
2019	42.565
2020	42.305
2021	42.054
2022	41.804