题目选项分析

Some economists view the Kennedy-Johnson tax cut of 1964, which radically reduced corporate and individual taxes, as the impetus for the substantial prosperity enjoyed by the United States in the late 1960's and early 1970's.

Which of the following, if true, would most weaken the claim that the tax cut of 1964 was the impetus for economic prosperity?

【选项】In the late 1960's, unemployment was relatively low compared with the early 1960's.