Year	Percent
1991	22.407
1992	22.269
1993	22.307
1994	21.917
1995	23.392
1996	27.371
1997	30.821
1998	32.54
1999	36.04
2000	39.3
2001	39.671
2002	41.104
2003	41.574
2004	41.626
2005	41.774
2006	42.836
2007	42.779
2008	42.599
2009	43.398
2010	44.265
2011	44.143
2012	44.716
2013	44.6
2014	44.895
2015	38.581
2016	42.104
2017	42.228
2018	42.664
2019	43.075
2020	43.431
2021	43.82
2022	44.18