In a report covering the past two-and-a-half years, the National Insurance Crime Bureau says the number of workers' compensation claims nationwide is falling year to year — from 3.35 million in 2011 to 3.24 million in 2012 — but questionable claims are rising, from 3,474 in 2011 to 4,460 in 2012.

Judging by statistics for the first six months of 2013, the bureau says these trends are likely to continue this year, with total claims dropping and questionable claims mounting in number.

California leads the pack in sheer volume of questionable claims, as does Los Angeles among cities, but Delaware is actually higher on a per-100,000-residents basis.

Questionable claims, the bureau says, consist of filings for exaggerated or fake injuries and/or claims for injuries not actually occurring at work.

The bureau's operations are financed by some 1,000 insurance companies nationwide .