Year	Percent
1991	30.24
1992	30.684
1993	30.866
1994	31.382
1995	31.781
1996	31.851
1997	33.537
1998	34.001
1999	34.399
2000	34.727
2001	34.946
2002	35.484
2003	35.903
2004	36.262
2005	36.612
2006	36.639
2007	36.809
2008	36.422
2009	36.397
2010	36.313
2011	35.801
2012	36.251
2013	38.38
2014	41.042
2015	40.639
2016	42.067
2017	42.029
2018	42.078
2019	42.343
2020	42.64
2021	42.958
2022	43.311