Year	Percent change (Units)
1980	11.927
1981	11.949
1982	5.862
1983	6.446
1984	6.056
1985	5.564
1986	3.467
1987	4.692
1988	8.835
1989	7.882
1990	9.051
1991	12.628
1992	4.849
1993	9.827
1994	11.268
1995	13.028
1996	10.782
1997	11.809
1998	7.807
1999	5.738
2000	3.587
2001	4.409
2002	3.535
2003	3.104
2004	4.566
2005	9.277
2006	7.923
2007	7.770
2008	11.995
2009	19.566
2010	10.103
2011	13.661
2012	11.004
2013	7.361
2014	8.621
2015	4.525
2016	2.864
2017	4.148
2018	3.925
2019	6.738
2020	10.741
2021	8.901
2022	12.148
2023	29.181
2024	24.757
2025	12.654
2026	7.570
2027	6.499
2028	6.493
2029	6.493