year: 2005
Total revenue (billion USD): 1.35

year: 2006
Total revenue (billion USD): 2.29

year: 2007
Total revenue (billion USD): 2.51

year: 2008
Total revenue (billion USD): 2.7

year: 2009
Total revenue (billion USD): 3.05

year: 2010
Total revenue (billion USD): 4.3

year: 2011
Total revenue (billion USD): 5.83

year: 2012
Total revenue (billion USD): 7.18

year: 2013
Total revenue (billion USD): 8.99

year: 2014
Total revenue (billion USD): 10.3

year: 2015
Total revenue (billion USD): 15.16