He declined to say how many white-collar jobs might be cut, but did say that reductions would come by not replacing retirees.

We know young families are replacing retirees.

Until recently, Chrysler had been hiring workers to replace retirees.

And with an unemployment rate of 2 percent, there are not enough workers to allow many new businesses to open, or existing ones to expand or even replace retirees.

Like most of Bloomfield, Whittle Avenue is in transition, according to Mr. Sorensen, with young families replacing retirees.

In news conferences, advertisements and a mobile sign towed around the county seat, the P.B.A. has been demanding that Nassau hire more officers to replace retirees.

The system is trying to recruit 2,000 new teachers even as it is laying off others, to meet the demands of growing schools or to replace retirees who taught required subjects.

Few have been hired since the 1980's, as the market share of General Motors, Ford and Chrysler has fallen, and as robots have replaced retirees.

At the same time, the younger people replacing retirees "are typically lower on the pay scale," he said, which saves the city money.

Even so, all but the first-rank schools have replaced retirees with part-timers.