Year	Percent change (Units)
1987	-34.571
1988	266.652
1989	34.668
1990	66.253
1991	67.589
1992	17.605
1993	5.280
1994	15.475
1995	29.864
1996	9.208
1997	-0.166
1998	-12.845
1999	-0.356
2000	-0.628
2001	0.567
2002	3.967
2003	2.942
2004	9.750
2005	8.836
2006	6.785
2007	12.685
2008	20.089
2009	6.376
2010	11.755
2011	18.137
2012	6.830
2013	6.021
2014	1.857
2015	0.612
2016	4.737
2017	2.597
2018	2.983
2019	5.232
2020	0.187
2021	1.813
2022	4.549
2023	3.581
2024	3.608
2025	3.400
2026	3.390
2027	3.390
2028	3.390
2029	3.390