| MES | 1950 | 1951 | 1952 | 1953 | 1954 | 1955 | 1956 | 1957 | 1958 | 1959 | 1960 | 1961 | 1962 | 1963 | 1964 | 1965 | 1966 | 1967 | 1968 | 1969 | Media |
| Enero | 89% | 83% | 77% | 73% | 71% | 81% | 82% | 81% | 71% | 70% | 65% | 73% | 69% | 80% | 74% | 76% | 72% | 63% | 58% | 81% | 74,4% |
| Febrero | 86% | 71% | 73% | 66% | 70% | 83% | 75% | 73% | 69% | 62% | 67% | 65% | 72% | 85% | 70% | 69% | 65% | 58% | 71% | 77% | 71,3% |
| Marzo | 82% | 67% | 69% | 65% | 71% | 66% | 73% | 77% | 64% | 67% | 65% | 66% | 70% | 57% | 69% | 64% | 64% | 53% | 65% | 71% | 67,2% |
| Abril | 71% | 64% | 69% | 61% | 75% | 63% | 68% | 76% | 59% | 62% | 63% | 68% | 64% | 60% | 55% | 62% | 60% | 60% | 63% | 75% | 64,9% |
| Mayo | 72% | 68% | 70% | 69% | 78% | 70% | 71% | 73% | 63% | 56% | 61% | 65% | 60% | 64% | 64% | 64% | 60% | 63% | 63% | 82% | 66,8% |
| Junio | 75% | 72% | 65% | 75% | 80% | 80% | 79% | 73% | 63% | 57% | 63% | 63% | 62% | 60% | 68% | 73% | 76% | 65% | 65% | 87% | 69,5% |
| Julio | 77% | 72% | 63% | 70% | 80% | 85% | 71% | 71% | 74% | 58% | 58% | 64% | 68% | 69% | 71% | 76% | 62% | 64% | 76% | 76% | 70,2% |
| Agosto | 77% | 71% | 63% | 71% | 82% | 86% | 70% | 80% | 59% | 56% | 65% | 64% | 59% | 70% | 71% | 68% | 60% | 69% | 79% | 82% | 70,0% |
| Septiembre | 71% | 70% | 69% | 72% | 84% | 85% | 77% | 77% | 66% | 60% | 64% | 74% | 61% | 63% | 73% | 68% | 68% | 69% | 78% | 88% | 71,8% |
| Octubre | 71% | 77% | 70% | 72% | 74% | 86% | 75% | 77% | 57% | 66% | 66% | 64% | 71% | 68% | 76% | 73% | 69% | 65% | 72% | 84% | 71,6% |
| Noviembre | 73% | 78% | 77% | 71% | 83% | 86% | 72% | 68% | 67% | 67% | 65% | 71% | 81% | 69% | 77% | 73% | 65% | 72% | 75% | 72% | 73,1% |
| Diciembre | 74% | 76% | 73% | 75% | 86% | 80% | 80% | 80% | 74% | 66% | 72% | 75% | 66% | 82% | 74% | 71% | 70% | 64% | 81% | 80% | 74,4% |