Year	Percent
1991	67.436
1992	68.907
1993	68.285
1994	69.093
1995	68.176
1996	67.882
1997	67.547
1998	67.143
1999	69.044
2000	41.942
2001	43.174
2002	43.022
2003	43.165
2004	42.269
2005	41.197
2006	41.512
2007	40.874
2008	40.292
2009	42.374
2010	40.163
2011	39.059
2012	39.281
2013	39.417
2014	40.125
2015	41.407
2016	42.358
2017	43.314
2018	43.304
2019	43.284
2020	43.262
2021	43.236
2022	43.209