Late last year, data firm Mattermark analysed follow-on rates for U.S. startups. Soon after, Dealroom did a similar exercise in Europe as part of Atomico’s State of European Internet report. But the two were never properly compared. Hence, below a side-by-side analysis, where orange is U.S. and blue is Europe. The ranges show different cohorts: Dealroom data is based on startups that were seeded between 2010 and 2013. Mattermark data is based…