Evolution item rarity?
Do we know whether some evolution items are rarer than others or if they are equally rare? The distribution I have gotten has been very uneven so far:
7x Sun Stone
4x Metal Coat
3x Dragon Scale
1x Up-grade
0x King's Rock
Of course, King's rock is the one I really need as I have plenty of slowpoke and poliwag candy.
Answers
I've obtained 4 sunstone, 2 metal coat, 1 upgrade, and kings rock. No dragonscale yet. Most people I know have received multiple sunstone so I would say it's the most common. As far as breaking down the actual percentages per item idk. I'm sure someone, somewhere has collected enough data to come up with a reasonable estimate. I wouldn't know where though.
Replying to myself here, but I just checked my stats. I have visited 2882 pokestops and received 15 evolution items in total. If we subtract the introduced 7 day guaranteed item, it would be 13 items. So that is a drop rate of 0,045%. On average you would have to hit a little over 200 pokestops to earn an evolution item.