According to Imperva DDoS report, over 75% of targets were hit multiple times in Q2 2017, while the percentage was only 43.2% in the same period of 2016. The report shows an increase in the amount of persistent application layer DDoS attack over a one-year period. The most targeted country is the US, assaults against the U.S. accounted for 79.7% of all attacks, while China remained the top attacking county. Multi-vector DDoS attacks accounted for 40.5 percent of all network layer attacks, a jump from 29 percent in the Q1.”]
Source: http://securityaffairs.co/wordpress/63747/hacking/imperva-report-ddos-q2-2017.html