Year	Number
1989	8.49758973752979
1990	7.47984718359583
1991	2.105836107606889
1992	2.320283525035664
1993	2.52254848078198
1994	3.4276180528217006
1995	2.432310225068447
1996	1.5124577325193025
1997	2.750451879569172
1998	2.241065275359499
1999	1.6086720908115013
2000	1.9843654715795225
2001	1.8423107182303828
2002	1.550021876158078
2003	1.4226462790992012
2004	1.6439619017060607
2005	1.5956049842410265
2006	1.4367422881399496
2007	1.3926767051281221
2008	1.4673385038638518
2009	1.7578871310239708
2010	2.136305228798975