Almost half of all companies have been the victims of a ransomware attack during the past 12 months, according to a new report. And while globally, 40 percent of them have paid the ransom, 97 percent of U.S. companies did not.Specifically, 75 percent of enterprise victims paid up in Canada, 58 percent in the U.K., and 22 percent in Germany, according to an Osterman Research survey of hundreds of senior executives in the U.S., Canada, German and the U.K.This is partly due to the fact that, in the United States, the attacks were much more likely to hit lower-level employees. In the U.S., enterprises reported that 71 percent of lower-level staff were affected, compared to 29 percent in the U.K., 23 percent in Canada, and 14 percent in Germany.In addition, U.S. infections were less likely to spread to other computers. Only 9 percent of U.S. respondents said that the infection had spread to more than 25 percent of endpoints, while other countries ranged from 17 to 41 percent."US organizations have less to lose by not paying, since far fewer endpoints are impacted by ransomware and less data will be lost as a result," the report said.However, attackers are increasingly targeting the more senior executives, said Nathan Scott, ransomware expert and technical project manager at Malwarebytes, which sponsored the report."There's a lot of motivation inside the ransomware world to try to find those guys, and now 25 percent of incidents attack senior executives and the C-suite," he said.Executives are more likely to pay up, he explained, as are larger companies."I've helped over 250 different types of people with ransomware alone, and every time I've helped an organization worth more than $10 million in assets, they never wait more than 10 hours to pay," he said.Plus, large organizations are willing to pay more."A normal computer user is hit for $500 to $1,000," he said. "But when an enterprise gets hit, we're talking $10,000 and up."Those who don't pay up restore from available backups and if that falls short, they will try to find other places where those files might be found, such as old emails, he said.The ransomware threat is growing quickly, Scott added, with a 43 percent increase in attacks in just the past six months."Ransomware is one of the fastest-moving security issues that we've had in IT," he said.The bulk of the ransomware attacks first entered an organization through user computers -- 49 percent via desktops, 36 percent by way of laptops, 5 percent through servers, and just 4 percent on mobile devices such as smartphones and tablets.Email was the primary channel, with 31 percent of infections coming in through email links and 28 percent through attachments. Other sources include web sites or applications other than email or social media, at 24 percent. Social media accounted for 4 percent of infections, and USB sticks for 3 percent.