A survey by the National Council of Churches showed that in 1986 there were 20736 female ministers, almost 9 percent of the nation's clergy, twice as much as 1977.
解答说可以改为twice as many as in 1977. 我怎么觉得不太顺,我觉得是twice as many as those in 1977. 其中those指代female ministers。 就有点像很早就接触到的句型:The weather of city A is better than that of city B.