Year	Percent change (Units)
1980	16.331
1981	-11.931
1982	-15.656
1983	1.331
1984	3.884
1985	7.221
1986	6.862
1987	14.347
1988	26.189
1989	10.700
1990	13.269
1991	7.525
1992	9.668
1993	5.296
1994	7.123
1995	5.366
1996	-5.899
1997	3.975
1998	8.141
1999	8.231
2000	5.582
2001	-3.979
2002	6.312
2003	-0.342
2004	-2.104
2005	4.303
2006	17.511
2007	10.865
2008	19.409
2009	-0.415
2010	8.205
2011	5.272
2012	5.466
2013	0.949
2014	3.450
2015	15.438
2016	7.024
2017	10.371
2018	8.447
2019	9.686
2020	-1.813
2021	7.575
2022	8.560
2023	8.665
2024	3.145
2025	2.876
2026	2.466
2027	2.322
2028	2.322
2029	2.322