Year	Percent change (Units)
1987	16.079
1988	18.640
1989	12.095
1990	3.977
1991	7.975
1992	5.875
1993	7.304
1994	8.207
1995	2.503
1996	1.257
1997	7.018
1998	1.989
1999	1.371
2000	7.684
2001	4.182
2002	-0.945
2003	1.111
2004	7.294
2005	-0.383
2006	1.127
2007	3.090
2008	1.836
2009	-11.678
2010	-2.733
2011	3.369
2012	-1.041
2013	6.431
2014	-1.587
2015	-0.624
2016	1.720
2017	7.049
2018	2.382
2019	-2.303
2020	-23.983
2021	27.639
2022	10.458
2023	5.300
2024	1.100
2025	1.000
2026	1.100
2027	1.100
2028	1.100
2029	1.100