Pension - is it North Carolina Source Income?

I now live in the UK but resided and worked in NC for many years. I receive a private pension from the company I worked for in NC, although that company is now headquartered in another State. As a non-resident, I am unsure whether a private pension is considered "derived from a business, trade, profession, or occupation carried on in North Carolina", or whether this relates only to current employment. Can anyone shed some light, please?