Year	Percent
1991	12.54
1992	12.751
1993	13.183
1994	13.517
1995	14.091
1996	14.833
1997	15.254
1998	15.48
1999	16.151
2000	17.262
2001	17.518
2002	18.632
2003	18.764
2004	17.662
2005	15.214
2006	16.327
2007	17.043
2008	17.959
2009	17.714
2010	19.97
2011	22.401
2012	23.91
2013	19.248
2014	19.737
2015	20.315
2016	20.955
2017	22.434
2018	23.059
2019	23.655
2020	24.324
2021	25.067
2022	25.416