People drink alcohol on St. Patrick’s Day — a lot of it.

It’s one of the biggest alcohol drinking days in the United States and a popular one for people to go out to the bar. Depending on which state you live in, whoever is serving up drinks may have a certificate from the government permitting them to do their job. It’s not true in most states, but the Institute for Justice points out that 13 states require some form of certification to work as a bartender.