I guess your definition of "right-wing" is a bit different from mine. "Centrists" in post-WW2 Europe are largely conservative: fundamentally religious, pro-business, anti-immigration. That, to me, is right-wing - respectable, not touting nazi tattoos (mostly), but still fundamentally reactionary in nature. Those blocs are usually allied with "liberal" parties, a term which in Europe carries right-wing connotations because "liberalism" is meant in the original economic sense: free-trade, unbridled capitalism, etc. Occasionally they ally even with ultra-right parties, which often include real neofascist / neonazis.
If you consider them like that, traditionally-conservative parties account for over 65% of current MEPs.