Year	Percent change (Units)
1980	-71.149
1981	-9.486
1982	105.795
1983	13.471
1984	-19.031
1985	-17.623
1986	3.454
1987	26.175
1988	5.040
1989	15.247
1990	20.700
1991	16.585
1992	4.300
1993	15.335
1994	6.279
1995	-21.537
1996	-0.800
1997	-14.210
1998	5.580
1999	2.606
2000	5.400
2001	-6.490
2002	9.248
2003	18.018
2004	-1.867
2005	-2.955
2006	6.384
2007	-3.472
2008	-4.186
2009	5.689
2010	7.875
2011	0.948
2012	-2.739
2013	-22.585
2014	19.240
2015	44.738
2016	16.440
2017	2.212
2018	-17.198
2019	-23.649
2020	6.641
2021	13.966
2022	1.287
2023	16.986
2024	7.699
2025	8.745
2026	3.901
2027	2.298
2028	1.940
2029	2.190