NEW YORK (CNN/Money) - Less than half of all Americans say they are satisfied with their jobs, according to a survey by the Conference Board. That marks the highest level of dissatisfaction since the survey was first conducted in 1995.

Only 20 percent of respondents said they are satisfied with their promotions and bonus plans, and only about a third said they are content with wages.

More on Jobs • Have you had it with your job? • Is your boss an idiot?

Workers aged 45 to 54 expressed the least amount of satisfaction, at 46 percent of respondents. The biggest decline, however, came from those aged 35 to 44. Levels of satisfaction for that group fell to 47.2 percent of respondents, from 60.9 percent in 1995.

Is anybody happy? Most respondents, it seems, were satisfied with their commutes and most like their coworkers. And -- not surprisingly -- the most satisfied households were those with earnings of more than $50,000. Even within that group, however, satisfaction declined markedly, to 53.4 percent of respondents, from 66.5 percent in 1995.

The survey is based on a representative sample of 5,000 U.S. households, conducted in July 2003.