Year	Percent change (Units)
1988	20.805
1989	18.749
1990	21.216
1991	-19.241
1992	-6.902
1993	-7.263
1994	-6.589
1995	-2.490
1996	-16.267
1997	3.679
1998	-7.030
1999	2.757
2000	3.745
2001	-4.773
2002	-14.829
2003	15.777
2004	54.709
2005	8.659
2006	7.854
2007	3.443
2008	-6.557
2009	-6.819
2010	-0.838
2011	-69.154
2012	217.460
2013	-23.803
2014	-54.813
2015	6.787
2016	2.709
2017	131.608
2018	43.112
2019	-9.895
2020	-68.888
2021	231.001
2022	15.967
2023	-16.370
2024	0.647
2025	1.696
2026	-0.850
2027	-3.780
2028	-2.994
2029	-2.911