According to Mr Esteve's figures, the correlation is roughly one international marriage for every two new migrants.

ECONOMIST: International marriage

Given the correlation among global stocks, Petrobras could be pulled down with international markets.

FORBES: What Forbes Readers Think About Brazil's Petrobras

The Third International Mathematics and Science Study, which tested randomly selected students from 41 countries, found no correlation between whether a country has national standards and how well its students perform.

CNN: Competition, Not Standards