Year	Percent
1991	40.238
1992	47.918
1993	54.886
1994	59.885
1995	66.13
1996	66.936
1997	55.545
1998	53.268
1999	50.143
2000	47.649
2001	48.143
2002	48.584
2003	53.64
2004	50.696
2005	51.368
2006	45.904
2007	48.095
2008	47.341
2009	49.947
2010	47.137
2011	45.63
2012	46.155
2013	44.595
2014	43.695
2015	43.794
2016	44.408
2017	43.469
2018	42.861
2019	42.202
2020	41.499
2021	40.685
2022	39.92