In an effort to justify its policies surrounding data service throttling for subscribers with unlimited smartphone data plans, AT&T on Tuesday issued a brief report regarding data usage on its nationwide wireless network. Senior EVP of AT&T technology and network operations John Donovan wrote on a company blog that data traffic on AT&T’s network has grown a staggering 20,000% over the past five years. Usage has doubled between 2010 and 2011 according to the executive, due in large part to the proliferation of smartphones. AT&T sold more smartphones in the fourth quarter of 2011 than in any other quarter in its history. And because its smartphone subscribers use so much data, AT&T seems to suggest it has no choice but to put measures such as data throttling in place. Read on for more.

“The growth is now driven primarily by smartphones,” the executive wrote on AT&T’s Innovation Space blog. “Add to that new customer additions and the continuing trend of upgrades from feature phones to smartphones, and you have a wireless data tsunami.”

While Donovan did not specifically address the recent resurgence of complaints surrounding AT&T’s throttling of unlimited data users, the timing of his blog post is no coincidence. AT&T’s questionable policy regarding unlimited data plans was brought back into the spotlight recently following a new wave of subscriber complaints. While AT&T currently offers a tiered 3GB smartphone data plan for $30 per month, unlimited data plan holders paying the same amount are often seeing their data speeds throttled — or slowed significantly in an effort to reduce network strain — after using less than 2GB of data in a single billing period.

Donovan offers no real solution, however he does stress AT&T’s continued investment in its network. “AT&T has invested more than $95 billion in its wireless and wireline networks over the past five years,” Donovan wrote. “In 2011, we invested $20 billion in our networks, and completed more than 150,000 wireless network improvements. And we expect to invest about $20 billion again in 2012 with a focus on wireless, including more 4G LTE deployment, the roll-out of distributed antenna systems in key venues across the U.S. and adding even more AT&T Wi-Fi Hot Spots to the nation’s largest Wi-Fi network.”

AT&T’s plan to address network issues by acquiring T-Mobile USA from Deutsche Telecom for $39 billion was canceled late last year after the United States Justice Department sued to block the deal.