I don't know that the number of sales matters, unless there are search engines that use that as part of their calculation.  I do believe that the number of images in your port matters.  Most sites will display more of your work once a client has found an image, and all will provide a link to your port.  I've seen way too many cases where a client buys several related shots at one time, and sometimes several unrelated shots.  Having a big port improves the odds of a client finding something else they'll like.