Year	Percent change (Units)
1980	23.594
1981	-19.640
1982	5.805
1983	-21.706
1984	8.629
1985	3.539
1986	17.286
1987	-5.009
1988	5.398
1989	-5.539
1990	18.108
1991	2.890
1992	-17.727
1993	-36.090
1994	11.556
1995	3.380
1996	15.254
1997	0.101
1998	5.191
1999	-2.026
2000	-8.396
2001	2.975
2002	17.616
2003	29.220
2004	-8.398
2005	0.679
2006	-4.202
2007	-7.999
2008	0.793
2009	29.140
2010	-0.786
2011	4.448
2012	12.401
2013	17.857
2014	-10.666
2015	-11.758
2016	5.812
2017	-0.051
2018	-1.896
2019	3.760
2020	18.809
2021	-10.205
2022	7.671
2023	2.145
2024	5.071
2025	5.663
2026	7.487
2027	8.158
2028	6.738
2029	6.095