Year	Percent change (Units)
1980	-9.220
1981	7.075
1982	-0.863
1983	-10.235
1984	-4.887
1985	8.108
1986	-13.147
1987	649.151
1988	-21.786
1989	32.262
1990	-5.320
1991	-3.309
1992	-12.897
1993	13.627
1994	2.667
1995	6.649
1996	6.778
1997	27.006
1998	-13.769
1999	-2.556
2000	12.252
2001	-1.704
2002	5.010
2003	-26.615
2004	2.579
2005	-6.075
2006	0.888
2007	5.321
2008	-12.378
2009	-13.610
2010	9.368
2011	4.305
2012	7.543
2013	-21.323
2014	19.639
2015	2.203
2016	13.919
2017	-1.712
2018	6.303
2019	-1.818
2020	-0.277
2021	-6.140
2022	-1.551
2023	8.026
2024	-0.112
2025	11.228
2026	4.772
2027	5.894
2028	4.119
2029	3.692