Year	Percent change (Units)
1987	3.487
1988	3.948
1989	4.306
1990	7.096
1991	3.725
1992	4.468
1993	6.415
1994	4.676
1995	3.122
1996	3.097
1997	2.784
1998	1.396
1999	3.724
2000	3.544
2001	2.518
2002	4.162
2003	2.287
2004	2.774
2005	3.787
2006	2.510
2007	9.920
2008	-1.859
2009	6.777
2010	-0.720
2011	6.121
2012	-3.715
2013	0.080
2014	2.201
2015	-0.926
2016	-0.881
2017	-0.462
2018	4.456
2019	3.580
2020	-3.067
2021	3.648
2022	5.735
2023	2.273
2024	1.815
2025	1.815
2026	1.998
2027	1.998
2028	1.998
2029	1.998