Year	Percent change (Units)
1980	-0.323
1981	13.648
1982	-6.224
1983	-6.401
1984	-20.252
1985	-12.786
1986	-2.625
1987	-0.211
1988	10.572
1989	23.370
1990	7.907
1991	3.155
1992	-17.933
1993	-22.478
1994	-6.564
1995	44.868
1996	27.183
1997	-10.628
1998	5.432
1999	-11.097
2000	-21.884
2001	64.203
2002	14.662
2003	38.839
2004	-2.096
2005	41.240
2006	-32.371
2007	0.699
2008	23.686
2009	7.798
2010	-9.761
2011	8.299
2012	17.172
2013	9.600
2014	-4.716
2015	16.175
2016	-35.660
2017	-5.395
2018	8.207
2019	15.038
2020	-14.040
2021	-21.901
2022	10.017
2023	1.102
2024	2.841
2025	3.797
2026	1.490
2027	3.132
2028	2.986
2029	3.316