Year	Percent change
1980	40.557
1981	22.33
1982	-2.456
1983	-28.994
1984	-20.714
1985	-16.512
1986	32.338
1987	8.191
1988	-15.726
1989	-25.212
1990	0
1991	23.064
1992	5.113
1993	3.259
1994	29.926
1995	28.424
1996	-0.881
1997	13.204
1998	2.415
1999	-18.045
2000	4.2
2001	0.971
2002	4.333
2003	3.529
2004	7.637
2005	10.41
2006	15.452
2007	20.669
2008	24.598
2009	-17.486
2010	27.198
2011	13.477
2012	10.364
2013	3.818
2014	-1.619
2015	0.183
2016	-3.014
2017	4.54
2018	1.572
2019	4.281
2020	5.273
2021	5.52
2022	4.336
2023	4.34
2024	4.072