Year	Percent
1991	25.101
1992	25.493
1993	25.868
1994	26.072
1995	26.283
1996	26.347
1997	26.56
1998	26.913
1999	27.602
2000	27.875
2001	27.72
2002	28.197
2003	28.396
2004	28.716
2005	29.219
2006	29.314
2007	29.297
2008	29.549
2009	29.491
2010	29.68
2011	30.396
2012	30.94
2013	31.864
2014	32.906
2015	34.15
2016	35.257
2017	35.904
2018	36.902
2019	37.823
2020	38.748
2021	39.606
2022	40.26