Employment costs rose 2.8 percent in the 12 months that ended in September, slightly less than they did in the year that ended in the previous quarter.
Employment costs rose 2.8 percent in the 12 months that ended in September, slightly less than employment costs(they) rose(did) in the year that ended in the previous quarter.比较的是那个2.8percent,
我的理解是,fewer是作为可数n.的比较。 这里XXX rose..., less than they rose last year. percent 也许可数,但increase是不可数的。 举例: 若是 Costs increase $2,000, 则可用 fewer than last year.