The newest post on Craigslist’s corporate blog says that in the past 12 months, the volume of listings in its Erotic Service categories is down 90-95 percent in five major cities, with sharp drop-offs following the company’s November initiative with 40 state attorneys general to clean up prostitution ads by requiring credit-card verifications.

The cities tracked include Atlanta, Chicago, New York and Craigslist’s hometown San Francisco.

A chart on the blog dramatizes the declines. Interestingly, in Chicago — hometown of Cook County Sheriff Thomas Dart, who last week sued Craigslist in an effort to get it to shut down Erotic Services altogether — activity in the category tracks higher than the other four cities. The chart represents the percentage of change over each month. It doesn’t divulge actual numbers.

What’s clear is that the Chicago sheriff struck a nerve — both with Craigslist and with the media, which was likely his intent, since the site’s right to publish Erotic-Service ads is generally protected by law. It’s also clear we haven’t heard the last of it, yet.

Craigslist says it donates all the proceeds collected from the category to charities.