Year	Percent
1991	41.23
1992	41.031
1993	41.559
1994	36.794
1995	37.318
1996	37.907
1997	38.445
1998	39.399
1999	37.232
2000	36.778
2001	37.334
2002	38.234
2003	37.142
2004	37.136
2005	37.733
2006	38.238
2007	38.235
2008	37.628
2009	39.016
2010	38.468
2011	38.439
2012	38.1
2013	38.187
2014	37.324
2015	38.603
2016	38.473
2017	38.192
2018	38.029
2019	38.322
2020	38.735
2021	39.445
2022	39.793