Year	Percent change (Units)
1980	0.000
1981	0.000
1982	0.000
1983	0.000
1984	0.000
1985	0.000
1986	0.000
1987	0.000
1988	0.000
1989	0.000
1991	38.420
1992	-9.416
1993	-1.166
1994	10.678
1995	-8.875
1996	-2.221
1997	5.877
1998	-7.538
1999	-18.344
2000	-63.738
2001	21.575
2002	43.887
2003	-0.990
2004	-20.517
2005	24.808
2006	3.938
2007	-30.013
2008	-13.391
2009	43.166
2010	11.257
2011	-15.480
2012	56.484
2013	-17.208
2014	27.946
2015	-28.058
2016	26.392
2017	20.090
2018	4.197
2019	-47.679
2020	24.307
2021	11.815
2022	-21.822
2023	28.432
2024	18.417
2025	8.599
2026	10.927
2027	10.532
2028	10.226
2029	11.236