Year	Percent change (Units)
1980	6.011
1981	9.880
1982	4.947
1983	-12.212
1984	22.765
1985	5.805
1986	-2.008
1987	1.316
1988	30.800
1989	20.736
1990	-4.750
1991	-1.349
1992	8.387
1993	5.695
1994	15.425
1995	9.839
1996	7.746
1997	12.743
1998	8.192
1999	10.351
2000	8.862
2001	-4.638
2002	14.120
2003	12.018
2004	14.349
2005	9.984
2006	9.451
2007	11.666
2008	10.289
2009	-9.637
2010	15.458
2011	10.409
2012	5.551
2013	-3.407
2014	0.149
2015	2.983
2016	0.203
2017	7.893
2018	3.773
2019	-0.846
2020	-2.194
2021	9.681
2022	7.266
2023	0.811
2024	1.285
2025	2.921
2026	2.422
2027	2.422
2028	2.422
2029	2.422