Selecting companies that are valued at over $1B yet haven't IPO'd yet is a really narrow set and a moving target. Why not include companies that were venture-ba

Selecting companies that are valued at over $1B yet haven't IPO'd yet is a really narrow set and a moving target. Why not include companies that were venture-backed and have IPO'd? And/or companies that were acquired for over $1B? For me the most interesting part of the underlying data is the number of Chinese companies.