From March 2001 to March 2012, the number of people who use their mobile devices to view their email has grown over 82%. So far iOS devices dominate this trend at 85%, but as we know, Android devices are growing in popularity everyday.

Return Path has come out with a new study that suggests that almost half of marketeers don’t know how many mobile subscribers they have. Why is this important? About 40% of mobile email viewers will delete a messages not optimized for mobile viewing. By the end of 2012 more people will open their email messages on mobile devices than on desktops.

The growing popularity of mobile devices is creating a real demand for advertisers and marketeers to rethink their email marketing strategies and make all their efforts mobile-friendly. This infographic is an eye-opening collection of stats that lets us all see the need for immediate action.

Take a look: