Year	Percent
1991	31.134
1992	32.696
1993	36.43
1994	35.195
1995	37.421
1996	38.957
1997	39.706
1998	39.888
1999	39.593
2000	40.073
2001	40.8
2002	41.402
2003	40.327
2004	41.177
2005	41.999
2006	42.3
2007	41.922
2008	43.015
2009	44.679
2010	45.332
2011	47.314
2012	47.332
2013	47.893
2014	50.18
2015	52.124
2016	51.867
2017	51.971
2018	52.195
2019	52.467
2020	52.816
2021	53.194
2022	53.572