Data breaches are on the rise, and preventing them is not as simple as it may seem.

A new report from Risk Based Security has revealed that convenience store and gas station chains seem to be highly susceptible to data breaches.

According to a report from Credit Union Times, Risk Based Security’s “Data Breach QuickView: 2015 Data Breach Trends,” has revealed that six of the Top 12 Repeat Offenders were oil companies and convenience stores, with Shell Oil and 7-Eleven ranking highest as one and two on the list, respectively.

The study also revealed that the number of data breaches rose 23% between 2014 and 2015.

The Credit Union Times also reported that the study found automated fuel dispenser skimming to be the most frequent form of data theft. Fuel dispenser skimming is achieved when a skimmer affixes a device to the card reader and captures card information when customers insert their cards into the ATM or fuel pumps. Cameras and video devices are also used to capture cardholder PINs when skimming ATMs.

Varying levels of security on card readers and on cards add to the difficulty retailers and consumers face when trying to protect information.

The Credit Union Times reported that the analysis found California to have highest number of data breaches in 2015, followed by Florida and New York which came in second and third, respectively.