Year	Percent change (Units)
1980	20.250
1981	12.717
1982	3.852
1983	10.500
1984	10.714
1985	9.078
1986	-1.387
1987	-14.936
1988	8.948
1989	-0.158
1990	1.608
1991	1.508
1992	-5.907
1993	-0.568
1994	24.289
1995	11.643
1996	6.452
1997	-0.673
1998	4.068
1999	-1.163
2000	-0.777
2001	5.184
2002	5.030
2003	-1.299
2004	-3.123
2005	6.390
2006	1.552
2007	1.414
2008	9.177
2009	2.376
2010	1.196
2011	2.956
2012	5.301
2013	-0.580
2014	0.892
2015	1.433
2016	-1.802
2017	2.388
2018	1.912
2019	-3.030
2020	0.481
2021	3.808
2022	9.734
2023	2.053
2024	1.000
2025	2.000
2026	2.000
2027	2.000
2028	2.000
2029	2.000