Five thousand of the 50, 000 books published in country Z in 1991 were novels  Exactly 25 of the films released in country Z in 1992 were based on those novels
Since 100 films were released in country Z in 1992, no more than one-quarter of them were based on books published in country Z in 1991
Some of the films released in country Z in 1992 were based on older films that had been released for the first time many years earlier.