WASHINGTON: This year’s US presidential election campaigns are breaking new ground not only for the tone of their messages but for how hard they’re trying to get Americans to listen to them. The volume of television advertising since January 2015 is up 122 percent from the same period four years ago, according to a new study by the Wesleyan Media Project released Thursday. Presidential campaigns and outside groups have spent a total of $408 million on 480,000 ad airings compared with $120 million on fewer than 220,000 advertisements by this point in 2012. Republicans are outspending Democrats, having shelled out two-thirds of the total amount so far from January 1, 2015 through May 8. Republican campaigns are airing ads at a volume of 80 percent more than four years ago, the report says. Democratic presidential candidate Bernie Sanders has been promoted by the highest number of ads—nearly 125,000—followed by Democratic front-runner Hillary Clinton, with 105,000 ads supporting her White House bid. Anti-Trump groups have aired around 17,000 ads.