Year	Percent
1991	26.388
1992	21.383
1993	19.553
1994	17.793
1995	15.777
1996	17.423
1997	18.625
1998	18.562
1999	20.712
2000	22.329
2001	24.531
2002	21.625
2003	25.273
2004	25.682
2005	27.456
2006	28.411
2007	28.498
2008	27.371
2009	26.128
2010	26.38
2011	27.309
2012	28.398
2013	28.271
2014	27.808
2015	27.614
2016	27.328
2017	27.466
2018	27.582
2019	27.675
2020	27.756
2021	27.829
2022	27.885