I am interested in doing a calculation of any piece of Japanese text to find an average number of words/kanji which are proper nouns, ie names of people or places. I assume this is a possible function in corpus analysis, but I am interested in how to generate my own data on the use of jinmeiyo kanji and hyogai kanji vs the standard joyo kanji.
Kuromoji might be able to help you, but I've never really tried it myself personally. I tested it on some NHK articles and it seemed to have correctly parsed out the 固有名詞 in those articles. And then if you were to collect a list of those 固有名詞 I suppose you could figure out the number of non-常用漢字 vs 常用漢字.