There are 114 Zizzi restaurants in the UK
Looking at Thompson it would appear there are 115 within the UK. http://www.thomsonlocal.com/businessFinder.aspx?phrase=Wimpy&where=United+Kingdom&origld=&ld=&originalWhere=
About 3000
one
well in the whole USA, there is 60,000,000 in and out restaurants.