COLLEGE PARK, Md. – When Florida’s pro-gambling groups launched a series of advertisements pushing voters to allow slot machines in 2004, they claimed gambling would rake in $500 million for state schools annually.

In reality, those slot machines have generated roughly $600 million in total for the state over six years – only 20 percent of what was promised.

Casinos have expanded across the country in the past two decades, as cash-strapped states have looked for new sources of revenue to plug their budget holes. Before 1989, only two states allowed casinos in the modern era – New Jersey and Nevada.