Year	Percent change (Units)
1980	-10.239
1981	-5.991
1982	15.815
1983	-13.745
1984	10.267
1985	5.040
1986	-20.016
1987	-2.074
1988	-16.769
1989	29.832
1990	-6.379
1991	8.388
1992	2.210
1993	4.604
1994	28.639
1995	5.680
1996	7.549
1997	13.713
1998	-7.040
1999	13.303
2000	9.766
2001	4.708
2002	3.979
2003	7.777
2004	11.280
2005	14.531
2006	-0.700
2007	1.672
2008	7.481
2009	0.197
2010	1.358
2011	5.653
2012	5.214
2013	-3.366
2014	-0.957
2015	2.900
2016	11.363
2017	8.014
2018	1.631
2019	1.223
2020	-13.882
2021	12.533
2022	3.341
2023	3.441
2024	-1.432
2025	2.030
2026	2.992
2027	2.662
2028	2.778
2029	2.569