Chart of percentage of 'failed' startups incubated Y Combinator, 2005-2019

I don't understand this graph. Weren't there 85+ startups in the class of 2019, example? https://techcrunch.com/2019/03/18/here-are-the-85-startups-t...

But the graph shows 0/2

So what's the rationale behind this data?

They got so much better at advising startups?

Startups are being insulated for real world truth eg. Due to too much funding?

Data is corrupted?

alt link https://static.wixstatic.com/media/aa3bfd_3310a0b27a5445cb9b...