Year	Percent change (Units)
1988	-5.296
1989	5.257
1990	52.884
1991	-1.654
1992	6.768
1993	34.122
1994	-23.705
1995	27.869
1996	28.046
1997	24.373
1998	0.861
1999	-2.533
2000	27.107
2001	-24.680
2002	17.395
2003	17.826
2004	20.882
2005	12.224
2006	7.503
2007	13.282
2008	-0.642
2009	-11.861
2010	17.443
2011	11.380
2012	1.324
2013	8.570
2014	-0.066
2015	2.514
2016	3.053
2017	8.975
2018	-8.113
2019	-4.021
2020	6.788
2021	3.181
2022	11.934
2023	15.154
2024	7.516
2025	2.008
2026	1.522
2027	2.551
2028	2.529
2029	2.659