Year	Percent change
1980	-29.111
1981	20.637
1982	8.509
1983	15.881
1984	22.861
1985	3.039
1986	19.745
1987	-10.247
1988	-39.838
1989	172.249
1990	-11.326
1991	9.362
1992	19.327
1993	65.154
1994	46.429
1995	32.878
1996	20.415
1997	0.37
1998	0.236
1999	-7.238
2000	-6.54
2001	5.545
2002	19.862
2003	20.718
2004	16.38
2005	6.951
2006	16.828
2007	33.336
2008	16.513
2009	-4.774
2010	4.404
2011	-3.708
2012	9.134
2013	17.119
2014	11.961
2015	16.134
2016	12.51
2017	17.379
2018	9.807
2019	13.254
2020	12.094
2021	12.149
2022	12.307
2023	12.289
2024	12.256