Year	Percent change (Units)
1980	-0.632
1981	-34.152
1982	-1.500
1983	-15.046
1984	-5.192
1985	-1.391
1986	-3.616
1987	-17.639
1988	-0.523
1989	1.321
1990	52.188
1991	-21.663
1992	0.601
1993	9.117
1994	-1.633
1995	0.621
1996	9.541
1997	0.185
1998	7.217
1999	-1.960
2000	3.729
2001	14.691
2002	13.019
2003	-22.481
2004	10.862
2005	44.720
2006	1.304
2007	119.540
2008	13.441
2009	-30.109
2010	-12.852
2011	5.548
2012	20.997
2013	13.541
2014	6.214
2015	-7.820
2016	17.833
2017	13.539
2018	-0.154
2019	3.406
2020	-17.764
2021	11.117
2022	3.176
2023	-5.957
2024	4.788
2025	11.714
2026	10.035
2027	7.426
2028	8.532
2029	7.048