Last year the rate of unemployment was 8.2 percent, but this year it has been 7 percent. We can conclude that unemployment is on a downward trend and the rate will be even lower next year.
Which of the following, if true, most seriously weakens the conclusion above?
【选项】
The unemployment figures were computed on the basis of a representative sample of economic data rather than all of the available data.
选项是否正确？