Year	Percent change (Units)
1980	-0.510
1981	5.105
1982	2.114
1983	4.059
1984	8.010
1985	12.590
1986	14.402
1987	3.924
1988	13.899
1989	8.983
1990	9.890
1991	0.376
1992	7.952
1993	0.583
1994	1.599
1995	1.749
1996	2.922
1997	-0.694
1998	6.286
1999	2.670
2000	0.049
2001	-3.409
2002	0.417
2003	4.264
2004	7.268
2005	-0.411
2006	6.488
2007	1.944
2008	4.881
2009	-1.885
2010	0.508
2011	4.863
2012	-0.379
2013	-2.222
2014	1.303
2015	-0.240
2016	3.805
2017	3.379
2018	2.861
2019	-0.200
2020	-23.586
2021	11.315
2022	15.674
2023	3.023
2024	2.442
2025	2.112
2026	1.768
2027	1.500
2028	1.500
2029	1.500