Year	Percent change
1981	52.174
1982	40.714
1983	-11.094
1984	159.083
1985	39.22
1986	38.26
1987	106.47
1988	120.59
1989	56.12
1990	264.97
1991	4227.98
1992	2729.79
1993	4583.08
1994	9796.90
1995	370.272
1996	1705.11
1997	20
1998	133.333
1999	485.714
2000	509.756
2001	135.09
2002	15.751
2003	4.443
2004	9.217
2005	20.988
2006	18.196
2007	9.964
2008	27.572
2009	53.438
2010	9.838
2011	8.654
2012	2.769
2013	1.074
2014	1.03
2015	0.889
2016	23.6
2017	55
2018	7.2
2019	7.1
2020	7
2021	6.9
2022	6.7
2023	6.5
2024	6.5