AT&T launched a big list of new 4G LTE markets this morning, opening up about 20 new markets across the US, including Puerto Rico. San Bernardino County in So-Cal has a few new markets to show off, while Michigan also got a hearty serving of improved mobile data speeds. AT&T is now right on Verizon’s heels in terms of the number of LTE markets available, and with all of the talks now surrounding LTE-Advanced, 2014 and 2015 should be a couple of great years for data speed.