Year	Percent
1991	52.402
1992	52.368
1993	52.45
1994	52.477
1995	53.19
1996	53.033
1997	52.922
1998	52.843
1999	52.839
2000	51.919
2001	51.118
2002	50.529
2003	49.966
2004	49.026
2005	48.963
2006	48.521
2007	48.452
2008	48.876
2009	50.014
2010	49.643
2011	51.7
2012	51.852
2013	52.509
2014	52.857
2015	53.084
2016	53.417
2017	53.711
2018	54.035
2019	54.367
2020	54.675
2021	54.974
2022	55.254