OKLAHOMA CITY (AP) - Despite a pair of U.S. Senate races, last week's primary election in Oklahoma had a tiny turnout, but the runoff election will be even smaller, with only five legislative contests to be determined.

The Aug. 26 runoff will cost the state between $65,000 and $80,000, estimates Mike Clingman, state Election Board secretary. He said the cost will range from about $12,000 to $14,000 in each legislative district involved.

Oklahoma is among less than a dozen states that still have runoffs. Most of them are in the Sunbelt, including bordering Texas. Arkansas also has runoffs, but has amended its laws to allow for “instant” runoffs for overseas voters.

“The trend has been to abandon runoffs or either have so-called instant runoffs (especially in local elections), Clingman said.

An instant runoff refers to a system where winners can be instantly chosen in a close contest because voters are asked to list their first, second and third choices for a particular office.

Critics of that system say it is confusing to some voters. Clingman said in some systems, it is technically possible that the person who got the highest number of first-place votes the first time around might not wind up winning.

There has been no big move to get rid of Oklahoma's runoff system, but Clingman said he would not mind seeing it abandoned because it causes so many headaches for election officials.

“From an election administrator's perspective, it is tough because of the four-week period you have to put on an election. It is impossible to get ballots printed and overseas in such a brief time span.”

Under pressure from a federal lawsuit, state election laws were changed so the ballots of members of the Armed Services could be counted in races for the U.S. House, Senate and for president. That results in a delay in certification of federal election returns.

The Oklahoma runoff system was abandoned at one time in the state's history, but was revived in the 1940s, Clingman said.

“I think, obviously at some point, somebody did not like who won and they put it back in,” he said.

Without a runoff system, some of Oklahoma's most famous politicians may never have achieved the popularity they enjoyed.

Democrat David Boren, former governor and U.S. senator, finished second in the primary in his first race for the House of Representatives. He won in a runoff.

In his race for governor in 1974, Boren came back from second place in the primary to upset the late Clem McSpadden for the nomination. Boren is now University of Oklahoma president.

In more recent times, Brad Henry got only 28 percent of the vote as he finished second to businessman Vince Orza in the four-candidate 2002 Democratic primary for governor.

Henry defeated Orza in the runoff and upset Republican Steve Largent in the general election. In 2006, Henry got 86 percent against the Republican nominee to win re-election.

Less than 329,000 voters showed up for Oklahoma's primary election this year, about 18 percent of the 1.8 million Republicans and Democrats eligible to vote.

Clingman says you have to go all the way back to 1944 to have such a low vote in a presidential year when there was a U.S. Senate primary. It was the lowest vote total in a primary since 1952, when a Corporation Commission race topped the ticket.

After lackluster Senate primaries this year, incumbent Republican Jim Inhofe and Democrat Andrew Rice advanced to the Nov. 4 general election.