Whats in the numbers?

With tomorrows European cup starting i wanted to gauge what the flavor of the month is regarding formations and how teams will play out of them. There are 16 nations competing in the tournament and the formation you will hear of allot this summer is the 4-2-3-1. As of today we can assume from press reports and likely styles of play that the 4-2-3-1 will be used by 6 of the 16 countries competing.