Rep. Henry Cuellar, D-Texas, sent the equivalent of 60.7 million official messages to his constituents from July through September 2014, unsolicited.

It’s not spam; it’s the congressional franking privilege.

The congressional frank, a holdover from the earliest days of the Republic, for two centuries gave members of Congress free mailing privileges. It remains alive in the Internet age, but in different ways: More members of the House of Representatives now use the frank to send nonmail messages than those who do.

Today, franking means more of an emphasis on radio, telephone calls and email, although official reports contain totals only for mail and nonmail communications. The messages can include radio ads announcing job fairs or town-hall-style meetings, constituent surveys and updates on official activity. A lawmaker’s email list or newsletter that you’ve actually signed up for is not counted; those communications aren’t considered franking.

A 2012 study by economists from Berry College in Georgia found that increased use of franked mail was associated with politicians who were seeking higher office, those in close elections and those whose districts were farther from Washington. But that might be changing because of the use of nonmail franking methods. Nine of the top 25 senders of franked mail in the House from Oct. 1, 2013, to Sept. 30, 2014, were involved in competitive races or retiring, but the same wasn’t true for those who used other methods. Of the lawmakers who used the other franking methods the most, just four were in competitive races or running for higher office and none were retiring. While lawmakers from states far from Washington did make extensive use of nonmail franking, so did some from Pennsylvania, Virginia and Ohio.

During that period, members of the House spent $22.3 million on franked mail and $6.7 million on other franked communications. The 295 lawmakers who sent at least one piece of franked mail during that period represent 68 percent of the House, which is down from previous years. From 1997-2008, an average of 84 percent of House members sent franked mail, according to a 2013 Congressional Research Service report.

Although there are other members of the House who regularly send messages to their constituents, Cueller and Rich Nugent, R-Fla., who made the equivalent of 40 million communications to his constituents during the third quarter of last year, stand out for their prolific efforts. The median lawmaker sent out 27,476 nonmail messages during the same time frame, the most recent period for which data is available.

The millions of messages from Cuellar that each of his 710,260 constituents received last summer were mostly radio ads. Use of the frank isn’t free; lawmakers pay for it from their official budgets. The figure, according to the Chief Administrative Officer of the House, which publishes details of official mass communication by congressional offices, comes from his use of radio to reach the residents of his southern Texas district, which stretches from outside San Antonio to the border with Mexico. When broadcasting ads on radio, congressional offices calculate the number of messages by multiplying the number of ads by the potential radio audience, which depends on the station.

"It is of the utmost priority for congressman Cuellar to serve the 28th District of Texas to the best of his ability within the tools he is allowed as a member of Congress," according to a statement from Kirsten Hartman, a spokeswoman for Cuellar. "Using the congressional frank to provide frequent updates and information allows the congressman to be as accessible and as helpful as possible to his constituents in Texas."

Nugent represents a district in between Ocala and Tampa, and frequent telephone town-hall-style meetings are a major reason for his large number of constituent communications. He tries to hold one each week when he’s in Washington, and he also uses radio to advertise events and casework services.

"The primary goal in everything we do is to try and make sure every person he represents knows how to reach him and what services are available to them," said Harrison Lewis, a spokesman for Nugent. "Obviously, people get their information in different ways, especially now, and it made sense to us not to rely on any one form of media."

As the Internet has become a fixture in congressional office operations, the number of mass mailings sent by lawmakers has declined. Between 1997 and 2012, an average of 82 percent of House members sent at least one mass mailing to an audience of at least 500 constituents, according to a Congressional Research Service report. But the volume of mail dropped to 61.4 million pieces in 2012 from 122.6 million in 1997.

In 2011, the House began reporting mail and other communications separately; it continues to do so every quarter. Not every member of the House uses the frank: 285 lawmakers sent no franked mail in the third quarter of 2014, according to official reports; a separate 197 didn’t send any mass communications of any kind.

Because the number of messages involve estimates and electronic media, the total cost, particularly for nonmail communications, rarely hits six figures. Nugent’s costs for the third quarter last year amounted to $8,100, while Cuellar’s were $31,148. In all, House lawmakers spent $1.7 million in that period on nonmail franking, compared with $5.6 million they spent on franked mail. Julia Brownley, D-Calif., first elected in 2012, spent $192,631 on franked mail during the third quarter, the most of any member of the House.

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