Year	Percent change
1981	27.414
1982	98.9
1983	80.701
1984	59.184
1985	63.739
1986	105.755
1987	159.174
1988	51.657
1989	19.697
1990	29.93
1991	18.795
1992	11.938
1993	8.009
1994	7.051
1995	51.966
1996	27.704
1997	15.719
1998	18.609
1999	12.319
2000	8.959
2001	4.403
2002	5.7
2003	3.977
2004	5.191
2005	3.333
2006	4.053
2007	3.759
2008	6.528
2009	3.574
2010	4.402
2011	3.819
2012	3.568
2013	3.974
2014	4.081
2015	2.131
2016	3.36
2017	6.773
2018	4.831
2019	3.08
2020	3
2021	3
2022	3
2023	3
2024	3