Before revision:  Using just ten minutes of labeled data and pre-training on 53k hours of unlabeled data still achieves 5.7 / 10.1 WER on the noisy/clean test sets of Librispeech.
After revision:  Using just ten minutes of labeled data and pre-training on 53k hours of unlabeled data still achieves 5.2 / 10.1 WER on the noisy/clean test sets of Librispeech.