stat.fallOneCm is broken

Put the summary of the bug you're having here

I thought I could use the stat.fallOneCm to track how much I'd fallen so I could do some cmd block things
Describe what you thought should happen here

It took me a while to realize that it wasn't tracking anything
Describe what happened here

Steps to Reproduce:
1. Create New World
2. do /scoreboard objectives add <Name> stat.fallOneCm
3. do /scoreboard objectives setdisplay sidebar <Name>
4. For more info, see video attached