claim: "an april study found that about 70 percent of ads in this election cycle have been negative [due to superpacs], up from only 9 percent through the same period in 2008."
author: sheldon whitehouse
evidence_1: may 2, 2012 ... “one reason the campaign has been so negative is the skyrocketing ... which  made up the bulk of the airings in 2008, were only 9 percent negative in 2008. so  far in this election cycle more than half of the ads sponsored by ... table 2 shows  that the total number of presidential ads (through april 22) was ...
evidence_2: "an april study found that about 70 percent of ads in this election cycle have been  negative [due to superpacs], up from only 9 percent through the same period ...
evidence_3: jul 16, 2012 ... an april study found that about 70 percent of ads in this election cycle have been  negative. that is up from only 9 percent through the same ...
evidence_4: "there have been at least 100 shootings each year [angel taveras] has been ... " an april study found that about 70 percent of ads in this election cycle have been  ... [due to superpacs], up from only 9 percent through the same period in 2008.
evidence_5: nov 16, 2016 ... the general election ads from the 2016 presidential campaign represented a ...  we also studied ads from two super pacs: one clinton-leaning ... 2, 2016,  clinton had spent $211.4 million in tv ads, while trump had spent only $74  million. ... platform for political ads with a 70 percent share of ad revenue.