Year	Percent
1990	3.82502
1991	3.67387
1992	3.52996
1993	3.40723
1994	3.25754
1995	3.64351
1996	3.46609
1997	9.021
1998	8.7641
1999	8.62384
2000	7.81901
2001	6.95889
2002	7.07214
2003	7.69136
2004	7.38309
2005	7.20396
2006	6.88658
2007	6.50609
2008	6.06351
2009	5.10071
2010	4.93292
2011	4.78705
2012	4.63411
2013	4.54927
2014	4.42031
2015	4.29378
2016	4.24122
2017	2.33149
2018	1.69959
2019	1.6726
2020	1.68005