I used to have pr 4 on one of my when it fairly new . The site would do 30-40hits a day , and id be lucky to break 1500 uniques a month and make a few hundred a month .
The site i speak of is now a pr2 , does over 20000 uniques a month , and is in the 5 figures .
Ive seen this on more then one site , so unless your selling links pr is useless