Year Xi | Observed | Observed |
1990 | 71.64 | −0.8657 |
1995 | 74.22 | −1.1371 |
2000 | 75.54 | −1.2908 |
2005 | 76.65 | −1.4323 |
2010 | 77.50 | −1.5487 |