Year	Percent
1991	30.839
1992	30.832
1993	30.832
1994	30.839
1995	30.889
1996	30.907
1997	30.937
1998	31
1999	31.087
2000	31.173
2001	31.254
2002	31.335
2003	30.885
2004	30.459
2005	30.029
2006	29.576
2007	31.291
2008	33.064
2009	34.864
2010	36.661
2011	38.447
2012	39.501
2013	40.574
2014	41.651
2015	42.835
2016	42.936
2017	43.244
2018	43.548
2019	43.843
2020	44.293
2021	44.7
2022	45.086