I've read a couple articles on keyword density. They mention that page content shouldn't exceed x% (around 8% often mentioned) keyword density. However, it's not clear to me whether it's x% per key word or x% for all keywords together. When reading the articles, it seems rather to be saying it's x% for all keywords together, but with so many words that could be counted as a "keyword", it doesn't make sense to me.
Thanks in advance!