Billionaires Jim Goodnight and John Sall, co-founders of software giant SAS, grew much, much richer in 2007, according to the list of the world’s richest people from Forbes magazine.

In the March 24 issue of Forbes now hitting newsstands, Goodnight is listed No. 102 among the world’s 1,125 billionaires, with a net net worth nearly doubling to $8.7 billion from $4.5 billion a year earlier. The growth of his fortune vaulted Goodnight 75 spots in the list of world financial elites.

Sall did even better percentage-wise as his net worth more than doubled to $4.4 billion from $1.6 billion, Forbes reports. He rose nearly 400 spots in the billionaire ranks to No. 236 from No. 618.

And neither man is considering retirement even as Goodnight, 65, and Sall, 58, reach the age where a life away from work beckons to most people.

“I see them every day, and I can tell you in terms of attitude, I don’t think retirement is even in their vocabulary,” Jim Davis, chief marketing officer and a 14-year veteran of SAS, told in an interview last week.

“Both of them are extremely wealthy, but you wouldn’t know that when you see them walking down the hallway,” Davis added.

SAS, one of the world’s largest privately held software companies, doesn’t disclose much in the way of financial information. However, the company did report that it topped $2 billion in revenue for the first time in 2007. The company also maintains that it has been profitable in the 32 years since Goodnight and Sall founded the company, when Goodnight was a professor at North Carolina State University. Sall studied statistics at NCSU.

Neither Goodnight nor Sall talk much about their fortunes. In fact, Sall rarely gives interviews.

Both men do remain very actively involved in product development at SAS, Goodnight in his role as chief executive officer and Sall as executive vice president.

SAS is gathering with customers from around the world this weekend in San Antonio, Texas, for their annual users’ conference.

Two other North Carolinians also remained on the Forbes list even though their portfolios didn’t do as well as did Goodnight’s or Sall’s. Financier Jim Spangler of Charlotte saw his ranking fall to No. 446 from No. 349 even though his net worth remained $2.6 billion. And motor sports mogul Burton Smith dropped to No. 962 from No. 618 as his net worth dipped to $1.2 billion, according to Forbes.

Warren Buffett, meanwhile, ended the 13-year tenure of Bill Gates as the world’s richest person with a net worth of $62 billion. Carlos Helu of Mexico rose to second at $60 billion. Gates is third at $58 billion.