Year	Percent
1991	73.247
1992	71.662
1993	70.353
1994	71.32
1995	72.643
1996	71.17
1997	72.725
1998	73.466
1999	74.587
2000	75.484
2001	71.842
2002	68.816
2003	65.198
2004	60.593
2005	56.906
2006	52.49
2007	47.279
2008	42.603
2009	37.735
2010	31.189
2011	30.11
2012	29.022
2013	28.336
2014	27.823
2015	25.753
2016	25.77
2017	25.696
2018	25.528
2019	25.135
2020	24.77
2021	24.423
2022	24.037