I used to go through lots of nickel rolls back in '74- '76. I wanted to make a roll set of all the dates in circulation. Of course the '50-D, '39-D etc were impossible but I got most of it including a whole roll of '71-P's that looked like this. It's a tough date.
Now days there are a lot of tough dates and some are very hard to find in BU rolls.
Time don't fly, it bounds and leaps.