Year	Percent change (Units)
1980	17.843
1981	-8.248
1982	-4.050
1983	-4.249
1984	3.796
1985	9.044
1986	-0.033
1987	14.029
1988	34.868
1989	11.077
1990	15.665
1991	5.394
1992	3.026
1993	5.874
1994	7.534
1995	10.032
1996	-5.921
1997	-1.684
1998	2.511
1999	10.125
2000	10.431
2001	-9.157
2002	1.242
2003	4.555
2004	-1.176
2005	5.986
2006	18.433
2007	8.130
2008	19.529
2009	-1.079
2010	8.217
2011	3.793
2012	3.773
2013	-1.246
2014	0.898
2015	19.266
2016	5.771
2017	5.571
2018	9.072
2019	10.510
2020	1.518
2021	5.074
2022	11.684
2023	4.646
2024	1.021
2025	2.090
2026	1.756
2027	1.561
2028	1.522
2029	1.522