Year	Percent change
1981	11.483
1982	0.4
1983	7
1984	3.2
1985	0.1
1986	13.9
1987	25
1988	41.2
1989	44.8
1990	40.4
1991	52.687
1992	27.335
1993	32.698
1994	75.409
1995	36.901
1996	51.716
1997	80.473
1998	20.846
1999	9.6
2000	9.6
2001	9.422
2002	9.031
2003	9.976
2004	15.244
2005	17.195
2006	24.562
2007	27.559
2008	24.834
2009	16.087
2010	12.89
2011	11.939
2012	10.406
2013	7.134
2014	6.426
2015	3.959
2016	5.123
2017	7.69
2018	9.045
2019	5.956
2020	5
2021	4
2022	3
2023	3
2024	3