Akamai Q1 Security Report: "Attack traffic [port] concentration increased significantly"

Akamai's The State of the Internet Report (Q1, 2012) reports about security/DDoS attacks as follows: "During the first quarter of 2012, Akamai observed attack traffic originating from 182 unique countries. China remained the top attack traffic source, responsible for 16% of observed traffic in total. The United States and Russia held the second and third place spots respectively, accounting for 18% of observed traffic combined. Attack traffic concentration increased significantly from the fourth quarter of 2011, with the top 10 ports seeing 77% of observed attack traffic [see chart below]. In the first half of 2012, Akamai’s support teams logged requests for assistance with 89 DoS attacks, primarily sourced from networks in the Americas and targeting American companies"

See "State of the Internet" - here.