Found this stat through a podcast:
"78% of right-footed penalties are scored compared with 63% of left-footed penalties." It's from CL-matches based on 211 non-shootout penalties, so it is quite remarkable actually.
It could be a freaky form of disadvantage for Messi, as he usually shoots with his left..
But I don't know - I also heard that it went wrong for him when he changed his style to making a decision as he walks up to the penaltykick, rather than in the moment he shoots - I'm not sure how one can tell the style-difference..