Akamai's State Of The Internet
One interesting observation about the ports that see the highest levels of attack traffic is that they were targeted by worms, viruses, and bots that spread across the Internet several years ago. While that’s not to say that there are not any current pieces of malware that attack these ports, it may point to a large pool of Microsoft Windows-based systems that are insufficiently maintained, and remain unpatched years after these attacks “peaked” and were initially mitigated with updated software.
There's an interesting rundown of the penetration of broadband access by percentage, ranked by country. South Korea is number one with 64 percent of its citizens getting greater than 5 Mbps. The US is 7th, at 20 percent, but of course 20 percent of the US is about 60 million people, more than the entire population of South Korea. Only Japan's 48 percent broadband penetration equals the total number of users of speedy Internet the US has.