• by Wayne Friedman , May 23, 2012

It may come as no surprise that spot TV is still the media-buying tool of choice for presidential candidates' advertising campaigns -- but local cable appears to be gaining.

During the first quarter, Nielsen says 75% of all advertising units were with over-the-air local television. But local/regional cable are gaining, now averaging 19% in terms of overall ad unit share of political candidates' media buys.

Rick Santorum used more cable advertising than any other candidate: 34% of the total number of ad units were on local or regional cable, with 59% of his ads on local TV. President Barack Obama scheduled the largest percentage of ad units for spot TV -- 83% -- with 16% going to local cable.

Mitt Romney easily logged in the highest number of commercial units, which includes broadcast TV, cable TV, newspaper and radio: 37,581 spots. Santorum was next at 9,231; Obama, 7,388; Gingrich, 5,978; and Ron Paul, 5,601.

Gingrich used the most spot radio: 13.1% of all ad units; Romney was next at 11.8%. Obama used the least radio, with just 0.9% of all his ad units.

Overall, the presidential candidate placed nearly 66,000 advertisements on local broadcast media, according to Nielsen.