TAMPA — For the first time, visitors staying overnight in Hillsborough County hotels, motels and other short-term rentals spent more than $600 million in a calendar year.The record-setting year means Hillsborough is now a "high-impact tourism" county, meaning county leaders can decide to raise the tax collected on each night's stay to 6 cents per dollar spent. The tax, called the Tourist Development Tax or sometimes the room tax, currently sits at 5 cents per dollar spent.For the elected officials who want to see the Tampa Bay Rays move to Ybor City, it's especially good news. Those like County Commissioner Ken Hagan have repeatedly seen the sixth cent as a way to help pay for a ballpark.There are two reasons the tax appeals to community leaders for the purposes of helping to finance a ballpark.First, it's a tax that mainly is paid by visitors to the area. Unless a residents takes a staycation at a Hillsborough County hotel, nearly all the money collected comes from out-of-towners.Taxing tourists more is seen as far more politically palatable than raising taxes on residents, like the contentious tax increase that paid for Raymond James Stadium. Hagan and others have said they will not support a tax increase on residents to pay for a ballpark.Second, local governments are limited in how they can spend taxes collected from hotels. State law dictates three uses for these tax dollars: tourism advertising and marketing; beach renourishment and financing for tourism facilities like convention centers, museums and, yes, stadiums. It cannot go toward things like teacher salaries or road repairs.With those limitations, the room tax has been attractive to the county to help pay for sports facilities. In recent years, it paid for upgrades to Raymond James Stadium, George M. Steinbrenner Field and Amalie Arena. Whether there is an appetite on the county commission to again leverage a penny of the room tax for another sports facility remains to be seen.The room tax won't cover all the costs of building a new ballpark. Far from it. Hillsborough County Chief Financial Officer Bonnie Wise estimated last year that the bonding capacity of the additional penny over 30 years is about $75 million.But Hagan and Wise have always said it will take a very creative financial package from multiple sources to help finance a ballpark. With Monday's announcement, Hillsborough cleared a major hurdle in unlocking one potential source.