How many plant eating dinosaurs were there?

That´s quite difficult to know for sure given the fact that we probably only know about 10% (probably even less) of the species of dinosaurs that ever existed. To try to get an idea you should think that there are more herbivores than carnivores (think of the energy pyramid) today and this has always been true in order to keep the balance in the different ecosystems. Now, mammals are like the group of animals that replaced dinosaurs in their different niches. Find out how many herbivorous mammals there are today (include the extinct ones) and you may get an idea of how many herbivorous dinosaurs there were.