Not surprisingly, penalty kick percentage varies very little across leagues:
Don't be fooled - Spanish players are no more likely to miss a PK. It's just a small sample size issue.
Here's the distribution of PK outcomes:
Of the 33 PKs we've seen in the World Cup so far, it's surprising to have seen four shots go wide or off the post already. We'll never get enough kicks to know if it's a real effect, but that won't stop commentators from telling us that world-class athletes fail more often under pressure.