So I've been playing. The .OSM data structure does not lend it self easily to this sort of thing. In particular you don't know when you read a line in if you want to count it or not. The critical thing is does the way include building= if it does then we are interested in every tag even those that have been read in previously.
I started following Bjenk's footsteps with R but realistically setting up the environment and parsing the file in R isn't that user friendly.
So I dropped back to Visual Studio express which is free from Microsoft. I've been working in the IDE environment and I have something that counts ways at the moment. Extending it to nodes is relatively simple once I have the ways working correctly.
I've just spotted that building types have an extra ' in the name. The Comma Separated Values (CSV) were working so they can be fed into a spreadsheet or some sort of stats program and 'Real Soon Now'™
it will be working once more.
The input is an .osm file so download and chop it up with OSMconvert64 to give the area you are interested in.I have sample .bat files available that do this.
What I need is someone who has use for the information to look it over
and give feedback. Please contact me directly not through the group.