Guess what, that is just the Philly ones. The Denver and San Francisco mints also have doubled die. But most are the Philly ones. Some of the DDO also include the master die doubling on them. These are mostly on the '2' on the date. But do you know what the biggest clue is on finding these? The '9' on the date:
The '9' gets affected the most. The stronger the doubling the 10:00 area is affected. Note the arrows on the images.