COLUMBUS, Ohio (AP) — Human trafficking investigations in Ohio rose last year to its highest level since the state started keeping track of such numbers.

The state’s attorney general’s Human Trafficking Commission issued a report last week that showed authorities investigated 202 human trafficking cases in 2017, a 50 percent increase from the previous year.

The majority of those cases involved the sex trade, The Blade reported.

Both the number of arrests and criminal convictions decreased, according to the commission’s report. There were 70 arrests last year, the lowest number recorded since 2013. There were 18 convictions, the lowest total since 2014.

State Attorney General Mike DeWine said he believes human trafficking convictions are “grossly underreported.” He said suspects are often not charged with the specific crime of “trafficking in persons.”

Of the 208 people identified as potential victims of human trafficking, the report found that 18 percent were minors. The report also found all but 10 of the 221 suspected traffickers were involved in the sex trade.

The report identified drugs, alcohol and other addictions as risk factors for victims in 100 cases last year. DeWine said the rise in human trafficking cases is connected to the state’s opioid addiction crisis.

“Drugs are used to control,” he said. “Because opioids are so addictive, it makes it easier for a pimp, makes it easier for a human-trafficker to control a victim.”

Ohio has changed its approach to human trafficking in recent years by increasing penalties and approaching those forced into prostitution as victims instead of criminals.

DeWine said the most important thing is saving the victim.