I haven't bought a box but a lot of packs. Wish I knew how many. Between my son and I we have pulled a FA Zekrom, FA Reg, Regular Reg, 3 FA Kyurem, the rare Hydregion (sp) and the rare Zororak. No MewTwo tho...
Wish I could tell you how many...probably, I'm embarrassed to say, between $150-$200 of individual booster packs and one Zekrom EX promo tin that I picked up today. That total is including the $50 for the pre-release.