(WBIR-Knox County) There are eight business parks now in Knox County, and they've become the hotbed of economic activity as of late.

"We got a lot of projects going on right now," said Todd Napier, the CEO of the Development Corporation of Knox County. On Tuesday, the group invited 30 business and county leaders to see the work that's been done over the last five years. That's the last time the organization did this kind of tour.

"Times were pretty tough. We had more empty buildings at that point," Napier said. "We were talking about some expansions..."

There were more than 6,000 jobs at these business parks in 2009. Today, these facilities hold a combined total of more than 8-thousand positions.

Businesses, like ADT at the Pellissippi Corporate Center, is one of those companies adding positions to the county tally. In the last year, they've expanded their regional call center by 50%, to now approximately 600 jobs.

"To come away with a little better understanding of what's here now-- what's growing now. And what's how can you continue to compete for jobs for businesses," Napier added.

Tour visited WestBridge, Hardin and EastBridge Business Parks, as well as the Pellissippi Corporate Center.