It’s linked in the article. The 85% accuracy is just shameless self promotion.

https://danluu.com/futurist-predictions/#:~:text=flowing%20i...

I'm going to need some evidence that Kurzweil was right in 80%+ of his predictions with several more on track.

What? no human in history has gotten anything 80% right. You're doing exactly what this piece complains about.