Year	Percent
1991	52.405
1992	52.592
1993	52.581
1994	52.332
1995	52.078
1996	51.72
1997	51.443
1998	51.775
1999	51.672
2000	51.429
2001	51.359
2002	51.216
2003	51.003
2004	50.423
2005	49.587
2006	48.979
2007	48.843
2008	48.226
2009	48.052
2010	47.301
2011	49.249
2012	48.918
2013	48.383
2014	48.563
2015	46.893
2016	46.839
2017	47.338
2018	47.807
2019	47.858
2020	47.816
2021	47.773
2022	47.709