| 1981 | +13.03% | +13.04% | +9.12% | −0.73% |
| 1982 |  | +13.07% | N/A | N/A | N/A |
| 1983 | | +13.11% | N/A | N/A | N/A |
| 1984 | +13.13% | +17.16% | N/A | N/A |
| 1985 |  | +13.16% | +12.73% | +2.62% | −0.10% |
| 1986 |  | +13.18% | +14.46% | N/A | N/A |
| 1987 |  | +13.28% | +11.29% | N/A | N/A |
| 1988 |  | +13.33% | +10.32% | +23.10% | −1.26% |
| 1989 |  | +13.36% | +16.02% | +15.15% | +0.10% |
| 1990 |  | +13.48% | +12.64% | +1.85% | −1.46% |
| 1991 | | +13.48% | +17.43% | +8.10% | −1.35% |
| 1992 |  | +13.49% | +12.48% | +11.39% | −2.18% |
| 1993 | +13.53% | +21.70% | +13.75% | +4.36% |
| 1994 | | +13.55% | +14.84% | N/A | N/A |
| 1995 | | +13.61% | N/A | N/A | N/A |
| 1996 |  | +13.62% | +23.08% | +13.07% | +3.40% |
| 1997 | +13.67% | +12.49% | +17.45% | N/A |
| 1998 | | +13.68% | +12.83% | +2.54% | −1.07% |
| 1999 | +13.71% | +23.18% | N/A | N/A |
| 2000 |  | +13.73% | +10.69% | N/A | N/A |
| 2001 | | +13.86% | +13.07% | +2.12% | −1.26% |
| 2002 |  | +13.90% | +17.75% | N/A | N/A |
| 2003 | | +13.93% | +17.77% | N/A | N/A |
| 2004 | | +13.95% | +23.29% | +14.43% | +4.33% |
| 2005 | +13.97% | +11.56% | +23.52% | N/A |
| 2006 | +13.98% | +11.56% | +23.51% | −1.05% |
| 2007 | +14.01% | +14.40% | +15.75% | N/A |
| 2008 |  | +14.01% | +9.69% | −4.05% | −3.84% |
| 2009 | | +14.01% | +23.42% | +14.81% | +4.76% |
| 2010 | +14.02% | +14.41% | +15.72% | +2.34% |
