| Año | Valor |
|---|---|
| 1990-01-01 | 48.942348 |
| 1991-01-01 | 57.249561 |
| 1992-01-01 | 52.446103 |
| 1993-01-01 | 56.657865 |
| 1994-01-01 | 46.600567 |
| 1995-01-01 | 41.835045 |
| 1996-01-01 | 44.008647 |
| 1997-01-01 | 45.074885 |
| 1998-01-01 | 41.940701 |
| 1999-01-01 | 46.019067 |
| 2000-01-01 | 50.128866 |
| 2001-01-01 | 53.479025 |
| 2002-01-01 | 52.640382 |
| 2003-01-01 | 45.688664 |
| 2004-01-01 | 47.334802 |
| 2005-01-01 | 39.975575 |
| 2006-01-01 | 43.025110 |
| 2007-01-01 | 42.542653 |
| 2008-01-01 | 38.869258 |
| 2009-01-01 | 36.859849 |
Fuente: World Bank