| Años | 1970 | 1971 | 1972 | 1973 | 1974 | 1975 | 1976 | 1977 | 1978 | 1979 | 1980 | 1981 | 1982 | 1983 | 1984 | 1985 | 1986 | 1987 | 1988 | 1989 | 1990 | 1991 | 1992 | 1993 | 1994 | 1995 | 1996 |
| Tasa | 190 | 182 | 150 | 143 | 134 | 173 | 180 | 185 | 213 | 228 | 261 | 263 | 292 | 333 | 362 | 351 | 361 | 380 | 399 | 390 | 375 | 438 | 410 | 340 | 482 | 523 | 382 |