Is there a slow down trend in the number of successful companies funded more recently, say in the last 4 years? I know it takes time for startups to become suc

Is there a slow down trend in the number of successful companies funded more recently, say in the last 4 years? I know it takes time for startups to become successful. it just seems that the pre 2015 era had more successful startups. That would mirror the broader trend we see in the marketplace of fewer and fewer successful startups.