The federal government has saved about $5.5 billion annually by moving to cloud services, but it might have saved up to $12 billion had efforts been more aggressive in moving from traditional, on-premise systems to the cloud, says a survey of federal IT managers.

The study was published by MeriTalk Cloud Computing Exchange.

The IT managers surveyed also reported spending 11 percent of their current, fiscal year 2013 budgets, or $8.7 billion, on cloud computing.

The chief impediment to implementing cloud services was security, listed by 85 percent of federal IT managers. Also of concern were agency culture, named by 38 percent of managers, and service levels, listed by 32 percent of managers.

Those most opposed to cloud implementation, according to the survey, were IT leadership, at 20 percent; program management, at 18 percent; and legal affairs, at 17 percent.

In the survey, 70 percent of respondents said they expected a rise in cloud applications in the next two years.

Asked to list the biggest driver of federal savings, the respondents ranked, in order: data center consolidation, cloud computing, big data, and bring-your-own-device.