Year	Percent change
1980	23.594
1981	-19.64
1982	5.805
1983	-21.706
1984	8.629
1985	3.539
1986	17.286
1987	-5.009
1988	5.398
1989	-5.539
1990	18.108
1991	2.89
1992	-17.727
1993	-36.09
1994	11.556
1995	3.38
1996	17.738
1997	0.085
1998	7.835
1999	-4.5
2000	-9.747
2001	4.354
2002	18.818
2003	30.441
2004	-6.236
2005	0.464
2006	-6.912
2007	1.602
2008	16.418
2009	11.21
2010	-3.218
2011	4.866
2012	13.658
2013	17.452
2014	-9.494
2015	-12.878
2016	6.016
2017	7.069
2018	3.591
2019	8.597
2020	8.129
2021	9.117
2022	8.723
2023	9.103
2024	8.786