This was a tough one to find. The WHO, CDC, and GPEI were referenced all over the web as sources, but I couldn't find any pre-compiled data tables. WHO had a data system that includes polio cases but it only went back to 2010.
Then - I found a citation in a PDF of WHO's Global Health Observatory reports. The report has the most recent data, but also a link back to a data series called the vaccines preventable diseases monitoring system. A search through that database, with some filtering, finally leads you to this:
http://apps.who.int/immunization_monitoring/globalsummary/timeseries/tsincidencepolio.html
It's country data from 1980 to 2014, reported cases of polio.
This also contains data on several other diseases: Diphtheria, Japanese encephalitis, Measles, Mumps, Pertussis, Rubella, Rubella (CRS), Tetanus, and Yellow fever.