Industrial output has grown by an average of ______ annually sin

Industrial output has grown by an average of ______ annually since tariffbarriers were eliminated in 1977.
A、3%
B、5%
C、8%
D、10%
【正确答案】：B
【题目解析】：自1977年取消关税壁垒以来，工业产量平均每年增长5%。