Year	Percent change (Units)
1980	-0.632
1981	-32.641
1982	-1.195
1983	-14.324
1984	-6.763
1985	3.209
1986	14.973
1987	-10.192
1988	-4.134
1989	-7.728
1990	43.032
1991	-15.780
1992	8.741
1993	15.023
1994	2.822
1995	5.056
1996	-4.203
1997	0.816
1998	12.932
1999	6.009
2000	6.987
2001	9.738
2002	29.823
2003	-20.031
2004	2.692
2005	24.589
2006	0.433
2007	32.721
2008	14.927
2009	-7.458
2010	-21.126
2011	4.994
2012	16.757
2013	14.284
2014	2.332
2015	-7.134
2016	19.110
2017	7.033
2018	-0.543
2019	1.837
2020	-20.743
2021	10.223
2022	6.205
2023	-3.686
2024	3.568
2025	10.116
2026	8.722
2027	6.039
2028	7.553
2029	6.996