U.S. top on list as source of botnet attacks

I found an interesting article on how the
U.S. tops list as source for botnet attacks, you can view it here. I found an interesting statistic which stated:

The United States was the top source of distributed attack traffic, originating nearly three times as many attacks as second-place China, according to a recent study by security service provider SecureWorks Inc.
The figures are based on identified attacks attempted against the company’s 2,000 customers so far in 2008. The bad guys launching the attacks were not always based in this country, but they used compromised computers in the United States to form botnets as platforms for the attacks.
According to SecureWorks, 20.6 million attacks originated from U.S. computers and 7.7 million from Chinese computers.