Year	Percent change (Units)
1991	22.099
1992	12.127
1993	10.791
1994	12.693
1995	8.591
1996	9.227
1997	7.380
1998	9.485
1999	8.564
2000	12.090
2001	9.044
2002	14.254
2003	2.576
2004	4.233
2005	3.585
2006	6.033
2007	5.523
2008	11.165
2009	7.926
2010	3.060
2011	7.397
2012	6.383
2013	4.894
2014	4.634
2015	3.696
2016	7.298
2017	5.167
2018	5.150
2019	2.588
2020	2.361
2021	4.494
2022	6.904
2023	5.523
2024	5.523
2025	5.523
2026	5.523
2027	5.523
2028	5.523
2029	5.523