Year	Percent
1991	1.448
1992	1.743
1993	1.963
1994	2.169
1995	2.504
1996	2.897
1997	3.321
1998	4.123
1999	5.054
2000	8.064
2001	13.574
2002	5.287
2003	4.785
2004	4.7
2005	4.765
2006	4.963
2007	5.255
2008	5.985
2009	5.744
2010	5.817
2011	5.78
2012	5.852
2013	6.064
2014	6.264
2015	6.277
2016	6.194
2017	6.473
2018	6.555
2019	6.678
2020	6.736
2021	6.783
2022	6.835