In a more limited survey of his organization's members in 1987-1988, the issue did not rank as one of the top issues.

The limited survey in areas heavily used by people suggests it is rather well able to persist at general levels of threat.

In 1990, a more limited survey by a bureau busy with the national Census found a 4.2 percent rate.

A more limited survey in 2001 estimated 300 gangs with 7,500 members.

She has designed and led several cited but often limited distributed nation-wide surveys in Afghanistan.

"Based on that very limited survey, they did pretty well," he said.

For example, he uses a limited survey to argue that wages are the most important concern of manufacturers.

Later, Werner Herberg conducted limited surveys around the site in the 1970s, before the Soviet invasion of 1979 once again cut off outside access.

Even the limited surveys, however, can offer a relatively good snapshot of comparative pay.

But limited surveys and anecdotes suggest that there is reason for concern.