115 players have had rookie seasons at greater than 61 points. So if you are intent on only counting rookies and sophmores and eliminating players like Taveres who broke into the league at 18 than you are probably right, 40-50 total.
Players under 23 that have done it back to back is going to be a whole lot higher. Which is the point of my post that you replied to above. You are looking at 40-50 players that have done that in just the last 20 years. It's actually probably a lot higher than that. I scoured hockeydb for all of 5 minutes picking names that I thought likely did it and I didn't go beyond 15th overall.
The rookie/sophomore thing is a nice bit of trivia but it doesn't mean much.