| Año | Valor |
|---|---|
| 1990-01-01 | 9.584100 |
| 1991-01-01 | 10.494000 |
| 1992-01-01 | 11.334800 |
| 1993-01-01 | 11.220900 |
| 1994-01-01 | 12.384500 |
| 1995-01-01 | 5.249300 |
| 1996-01-01 | 4.851000 |
| 1997-01-01 | 7.605200 |
| 1998-01-01 | 4.416900 |
| 1999-01-01 | 4.290200 |
| 2000-01-01 | 3.654600 |
| 2001-01-01 | 2.918700 |
| 2002-01-01 | 3.165800 |
| 2003-01-01 | 3.370100 |
| 2004-01-01 | 3.082300 |
| 2005-01-01 | 2.999700 |
| 2006-01-01 | 2.576900 |
| 2007-01-01 | 2.451100 |
| 2008-01-01 | 2.554300 |
| 2009-01-01 | 2.452400 |
Fuente: World Bank