Year	Percent change
1981	4.126
1982	12.731
1983	15.385
1984	24.681
1985	25.455
1986	52.301
1987	15.317
1988	12.418
1989	8.394
1990	10.487
1991	11.553
1992	4.246
1993	5.128
1994	5.043
1995	4.039
1996	2.253
1997	0.309
1998	4.779
1999	1.749
2000	0.203
2001	8.069
2002	13.005
2003	17.564
2004	8.09
2005	4.846
2006	0.423
2007	6.02
2008	6.835
2009	2.718
2010	5.789
2011	4.382
2012	4.908
2013	5.575
2014	6.95
2015	6.667
2016	7.875
2017	6.945
2018	6.447
2019	6.477
2020	5.505
2021	5.011
2022	5.011
2023	5.011
2024	5.011