Medicare paid out $60 billion in erroneous and fraudulent payments in 2016, according to a new Government Accountability Office report. An estimated $16.2 billion of that total went to health insurers that participate in the Medicare Advantage program.

Why it matters: Medicare spent nearly $700 billion of taxpayer money on health care services last year, meaning nearly 9% of those payments were improper. A top GAO official testified Wednesday that billing and medical coding errors are especially widespread in Medicare Advantage, which is way behind on scheduled audits called "risk adjustment data validation," and that more needs to be done to monitor payments.

Reminder: Many Medicare Advantage plans are under scrutiny and have faced allegations they are exaggerating patients' medical codes to get higher payments.