Year	% of revenue
2005	30.133966108036454
2006	25.52799142870525
2007	22.245104457179707
2008	22.779377742449622
2009	28.822483655456
2010	31.192070115672394
2011	18.210279600592152
2012	21.199221076934737
2013	22.82176161919444
2014	20.11322481410955
2015	25.672679880811334
2016	23.8722183921813
2017	25.17323470595639
2018	21.130658347804417
2019	25.10768004930795
2020	25.920822865226782