Year	Percent change
1981	25.37
1982	44.71
1983	83.127
1984	52.279
1985	74.527
1986	116.347
1987	116.797
1988	38.328
1989	85.543
1990	98.286
1991	115.377
1992	34.799
1993	26.69
1994	17.73
1995	34.527
1996	6.379
1997	66.923
1998	-5.677
1999	36.745
2000	-3.052
2001	3.432
2002	-3.08
2003	11.286
2004	14.391
2005	13.1
2006	8.263
2007	13.763
2008	9.278
2009	7.54
2010	7.403
2011	6.63
2012	6.21
2013	5.375
2014	4.618
2015	8.38
2016	17.412
2017	15.326
2018	17.522
2019	14
2020	12
2021	10.2
2022	9
2023	8.5
2024	8