I've been kind of obsessed with this in 2018. I had a competition with a colleague to get contributions every day for a month, and I've continued since.
I don't want my real email address in every commit, so I often used mark@pcname in the past. I missed out on a lot of green squares that way! I fixed it halfway January...
(The holes in the last weeks are commits that are still on feature branches that haven't been merged. They don't count until they're in master).

No work contributions on here, we use subversion for that.