Scoreboard bug with skulls

I wanted to make a scoreboard to testfor if a player mined a head.It looked like this:

/scoreboard objectives add LuckyBlock stat.mineBlock.minecraft.skull

I first noticed that when i pressed TAB before writting "skull" it didn't work so i wrote it myself.But it didn't work and said "Invalid objective criteria type 'stat.mineBlock.minecraft.skull".I'm not sure if it's a bug or they didn't add it yet