Historically, what percent of startups at series A, B, etc end up going out of business? A material percentage I think? These companies, are they going through

Historically, what percent of startups at series A, B, etc end up going out of business? A material percentage I think? These companies, are they going through a modern "failure" where it turns out loom or whatever is not a viable business, but instead of just imploding, they die slowly because VCs don't want to write down their investments, so they make them stay on life support?