As far as I can tell, the donations work like this:

Every day, the votes are counted from the day's blocks. The donation amount is calculated as 1% of the day's emission times the percentage of "yes, donate" votes. Then 1% of the day's emission is subtracted from the not-yet-donated amount (which starts out as 1% of the total supply). Then the donation amount is rounded down to get rid of dust.

Basically this has the same effect as if when each miner votes "yes, donate" 1% of the block reward goes to the developer, and if they vote "no" nothing goes to the developer.

You can correct me if I'm wrong.