Washington (CNN) The State Department's government watchdog has released a review of its email record-keeping practices and concluded that the vast majority of emails sent by State personnel are not being preserved, possibly in violation of the Federal Records Act.

Out of the billion emails sent by personnel in 2011, the Office of the Inspector General found that only a minuscule fraction -- 61,156 -- were actually recorded within employees' official email accounts. That number dropped to 41,749 in 2013.

This information comes amid controversy over former Secretary of State Hillary Clinton's use of a personal email account while in office, which brought renewed attention to the State Department's record keeping policies -- policies which rely on employees' self-reporting.

At a press conference on Tuesday, Clinton said her team complied fully with the State Department by submitting emails they deemed "work-related," but this has not stopped some Republicans from demanding her full cache or emails be turned over for review.

Rep. Trey Gowdy, who is chairman of the House Select Committee on Benghazi , said Tuesday that only an independent third party could be trusted to decide which emails qualify for preservation.

"She said she went through and produced all public information -- and I am not in the habit of accusing people of being untruthful unless I have evidence to the contrary -- but she's essentially asking us to take her word for it," said Gowdy.

Also at issue was why Clinton claimed to have had private email as a matter of "convenience" so she could only carry around one device. Many critics mocked her, noting their devices have multiple emails setup in them.

But according to a senior state department official speaking on background, Clinton's explanation makes sense given the agency's restrictions.

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"Prior to early 2014 and the release of a new generation of Blackberry devices, the security protocols that State deployed did not permit automated access to personal email accounts," the official told CNN.

The State Department exclusively gives out BlackBerry phones to its employees, but given this policy, she would have had to use a personal device, the official said.

BlackBerry's operating system allowed for dual email accounts prior to when Clinton left office in 2013, a Blackberry spokesperson told CNN on Tuesday, so the one-address policy was a State Department decision, not a technological capability issue.

But even State Department personnel using State.gov email addresses have discretion in what emails are kept for archiving. And their compliance is at the heart of the OIG's review.

Specifically, the review cites department personnel for inconsistent use of a program called the State Messaging and Archive Retrieval Toolset (or SMART), which allows them to flag emails for retention within the Microsoft Outlook email application.

Six years after SMART was implemented, the OIG asserts, "Department of State employees have not received adequate training or guidance on their responsibilities for using those systems to preserve 'record emails.'"

Photos: Hillary Clinton email controversy Hillary Clinton, while U.S. secretary of state, checks her Blackberry on a military plane in October 2011. Clinton said she used a private email account for her official work at the State Department and that she did so out of convenience. But she admitted in retrospect "it would have been better" to use multiple emails. Hide Caption 1 of 7 Photos: Hillary Clinton email controversy Clinton checks her phone after addressing the U.N. Security Council in March 2012. Hide Caption 2 of 7 Photos: Hillary Clinton email controversy Clinton looks at her phone after attending a Russia-U.S. meeting in Hanoi, Vietnam, in July 2010. Hide Caption 3 of 7 Photos: Hillary Clinton email controversy Clinton types on her phone during a visit to Brasilia, Brazil, in April 2012. Hide Caption 4 of 7 Photos: Hillary Clinton email controversy Clinton hands off her phone after arriving to meet with Dutch Foreign Minister Uri Rosenthal in The Hague, Netherlands, in December 2011. Hide Caption 5 of 7 Photos: Hillary Clinton email controversy Clinton speaks on a phone in the lobby of a Honolulu hotel before briefing reporters on the Haiti earthquake in January 2010. Hide Caption 6 of 7 Photos: Hillary Clinton email controversy Clinton looks at a phone with Assistant Secretary of State for European Affairs Philip Gordon as they wait in a Munich, Germany, conference room for a bilateral meeting with the Ukrainian President in February 2012. Hide Caption 7 of 7

The Federal Records Act and State Department guidelines laid out in the official Foreign Affairs Manual require personnel to preserve emails related to "the organization, functions, policies, decisions, procedures, and essential transactions of the agency."

But the manual puts the onus on employees to decide what emails qualify, advising them to "exercise the same judgment they use when determining whether to retain and file paper records."

The OIG report found that the policy is applied inconsistently within the department and there is an alarming lack of understanding among employees what the law actually requires.

In interviews with department employees, the OIG noted, "many officers and employees -- not just those new to the Department -- had little idea about what makes an item of information a record."

"This general lack of understanding, which extends to records in all forms, is a major obstacle to the use of record email," the report further concludes. "OIG interviews revealed that some employees learned about record email in training about using the SMART software but were not aware of any requirement to use it."

State Department deputy spokeswoman Marie Harf said since the inspector general is independent from the department "they will have to speak to the timing and details of releasing this report, which they control."