On se u 2006. i 2007. suzio na 12,5%, u 2008. se proširio na 13,6%, a zatim u 2009. na 15,3% i u 2010. na 15,7%.
It narrowed to 12.5% in 2006 and 2007, widened to 13.6% in 2008, then to 15.3% in 2009 and to 15.7% in 2010.