plagiarism statistics

In 2012 Proceedings of the National Academy of Sciences, an American journal, published a study of retractions accounting for nation of origin. In it a team of authors wrote that in medical journal articles in PubMed, an American database maintained by the National Institutes of Health, there were more retractions due to plagiarism from China and India together than from America (which produced the most papers by far, and so the most cheating overall).