Year	Percent change (Units)
1980	26.531
1981	24.019
1982	26.608
1983	30.566
1984	33.659
1985	45.625
1986	59.996
1987	26.512
1988	62.864
1989	65.338
1990	-0.874
1991	123.578
1992	117.624
1993	101.305
1994	115.478
1995	68.375
1996	86.764
1997	47.169
1998	24.622
1999	17.166
2000	7.121
2001	1.935
2002	22.225
2003	6.489
2004	9.658
2005	8.506
2006	7.199
2007	14.754
2008	14.297
2009	11.257
2010	12.978
2011	18.097
2012	35.559
2013	36.522
2014	36.907
2015	16.910
2016	17.750
2017	32.352
2018	63.293
2019	50.994
2020	163.258
2021	359.092
2022	138.808
2023	171.471
2024	145.535
2025	62.726
2026	25.184
2027	15.807
2028	8.474
2029	8.337