Growth was impressive in the 1950s and 1960s, in some estimates much higher than during the 1930s, but later declined and according to some estimates became negative in the late 1980s.
1950年代和1960年代的增长给人印象深刻，一些估计比1930年代的还高，但后来下跌并且根据一些估计在1980年代末为负值。