Year	Percent change
1981	14.384
1982	37.831
1983	-1.964
1984	-7.925
1985	-8.569
1986	3.528
1987	-4.874
1988	-3.421
1989	2.865
1990	5.774
1991	223.966
1992	9.589
1993	15.487
1994	5.714
1995	4
1996	4.516
1997	3.681
1998	5.74
1999	3.652
2000	5.817
2001	3.333
2002	4.523
2003	3.088
2004	5.924
2005	7.763
2006	10
2007	8.235
2008	16.929
2009	1.341
2010	15.41
2011	5.541
2012	7.733
2013	5.675
2014	8.378
2015	1.586
2016	3.122
2017	1.325
2018	1.027
2019	1.137
2020	2.157
2021	2.487
2022	2.637
2023	2.881
2024	3