(Fortune) -- Steel Dynamics (Charts) ranks no. 46 on Fortune's 2006 list of the 100 Fastest-Growing Companies. The Fort Wayne, Indiana-based company saw profits rise at a rate of 66% and revenues grow 45% with a stock return of 69% on average annually over the past three years. The company ranked 31 on the 2005 list.

Each year, Fortune's ranking of Fastest-Growing Companies provides a snapshot of America's economy, and this year the picture is drenched in oil. Last year 18 energy firms cracked the top 100 - up from four in 2000. Now more than a third of the roster - 34 companies - are in the energy biz.

But oil is hardly the whole story. Computer and biotech firms make their usual strong showing. Catering to Americans' obsession with how they look (and how well they see) has been remarkably lucrative: LCA-Vision, a laser surgery provider, lands at no. 5, followed closely by Palomar Medical Technologies, which makes laser devices used in cosmetic skin treatments.

This year, just two homebuilders made the cut: Toll Brothers at No. 98 and Meritage Homes at No. 99. Last year there were four homebuilders and two land developers on the list.

Fortune's 100 Fastest-Growing Companies list is an annual ranking of U.S. companies by three-year growth in sales, profits and total return that meet key criteria for sales, profit and market capitalization size and sales and profit growth.

Companies on this year's list include: Comercial Metals (Charts), United States Steel (Charts), Nucor (Charts), Schnitzer Steel (Charts), and Quanex (Charts).

Next: Full list: 100 Fastest-Growing Companies at http://www.money.com/fastestgrowing

Plus: See Steel Dynamics's Fastest-Growing details, including financial stats and contact information.