The National Human Trafficking hotline, operated by the nonprofit Polaris, reported a more than 35 percent increase in the illegal activity in the U.S. last year.

The states with the most cases were California, Texas and Florida.

International efforts are ongoing to limit human trafficking and punish offenders. Awareness has been raised, but activists consider it to be an uphill battle.

The McCain Institute held its second-annual Human Trafficking Symposium this week, and we spoke with Cindy McCain about priorities going forward, including increasing penalties for human traffickers.