Year	Percent
1991	34.855
1992	36.364
1993	39.464
1994	44.054
1995	45.405
1996	45.999
1997	44.077
1998	41.561
1999	42.977
2000	45.023
2001	44
2002	40.052
2003	40.377
2004	41.452
2005	43.918
2006	43.629
2007	43.723
2008	44.439
2009	44.659
2010	44.22
2011	42.845
2012	42.513
2013	43.075
2014	43.19
2015	43.452
2016	44.308
2017	44.694
2018	44.897
2019	44.747
2020	44.553
2021	44.321
2022	44.063