A joint study by the U.S. Department of Homeland Security and the FBI revealed that 79% of mobile malware attacks were directed at Android in 2012. Now, according to the H2 2013 Threat Report from security firm F-Secure, Android’s lion’s share of mobile malware has grown to 97% in 2013.

Android malware threats

According to the report, Android malware rose from 238 threats in 2012 to 804 threats made up of new families and variants of malware in 2013. Most of the threats came from outside the U.S., with 75% of malware detections originating in Saudi Arabia and India. Only 5% of the malware affected U.S. devices.

(Related: The best and worst Android security apps)

The report also stated that while the majority of malware infected devices via third-party app stores, the Google Play Store itself accounted for only 0.1% of Android malware. In the Android markets worst affected by mobile malware attacks, the Google Play Store is either limited or not yet supported.

“The Play Store is most likely to promptly remove nefarious applications, so malware encountered there tends to have a short shelf life,” the report said.

For more information, check out the full F-Secure Threat Report for 2013.