Year	Percent
1991	49.245
1992	49.091
1993	48.943
1994	50.217
1995	50.059
1996	50.596
1997	50.946
1998	51.362
1999	52.307
2000	51.378
2001	50.644
2002	49.722
2003	48.442
2004	50.511
2005	50.972
2006	51.345
2007	51.68
2008	51.617
2009	52.832
2010	52.376
2011	50.869
2012	53.747
2013	53.16
2014	53.209
2015	54.373
2016	55.235
2017	55.709
2018	56.654
2019	57.659
2020	58.524
2021	59.307
2022	60.155