Mariah Carey looks certain to debut at No. 1 on next week's Billboard 200 with "E=MC2," based on massive first-day sales from the nine chains that report to Nielsen SoundScan's Building Chart. Unweigh

Mariah Carey looks certain to debut at No. 1 on next week's Billboard 200 with "E=MC2," based on massive first-day sales from the nine chains that report to Nielsen SoundScan's Building Chart.

Unweighted sales for the Island Def Jam album are at 154,000 units on the report released today (April 16). That's more than five times the total garnered by the current chart-topper, Leona Lewis' "Spirit" (Syco/J).

By comparison, Carrie Underwood's "Carnival Ride" (Arista Nashville) had first-day sales of 150,000 and wound up shifting 527,000 in its first week.

Billboard estimates that the merchants who report to the Building Chart -- Trans World Entertainment, Starbucks, Best Buy, Circuit City, iTunes, Border's, Target, Anderson Merchandisers, and Handleman Co. -- represent 80% of the U.S. retail market.

Carey's last release, 2005's "The Emancipation of Mimi," debuted at No. 1 on The Billboard 200 with first-week sales of 404,000 copies.