Year % of GNI 1990 2.53934284556125 1991 3.04207136680371 1992 2.89448942081829 1993 2.77616775718644 1994 2.46995101642623 1995 2.36867133821434 1996 2.31370424838393 1997 2.22418196038204 1998 2.21729301500833 1999 2.26776936887605 2000 2.12086608804526 2001 2.51528634585818 2002 3.0602022606688 2003 3.48601869914741 2004 4.05725846981114 2005 4.22426737513072 2006 3.87880842049299 2007 3.58861201937385 2008 3.10490078432229 2009 2.88370477690568 2010 2.66728882787385 2011 2.66929751963829 2012 2.45016410185952 2013 2.45993788889887 2014 2.47305638302717 2015 2.43102497234033 2016 2.53188648141044 2017 3.92080745916321 2018 3.98992208888323 2019 3.48169795265612 2020 3.04956970680007 2021 3.00877092849729