Mushrooms: 5 red, 10 yellow, 21 blue, 8 green, 9 black, 9 brown
Non: Blueberry 7, branch 20, corn 11, cotton, lingonberry 8, onion, potato 11, raspberry 4, rice 4
'''Mushroom ratio: 48%'''
Aug 17: (19 skill, otherwise identical conditions)
Mushrooms: 9 red, 7 yellow, 9 blue, 11 green, 14 black, 9 brown
Non: Blueberry 3, branch 16, corn 9, cotton 4, lingonberry 5, onion 5, potato 6, raspberry 4, rice 2, cocoa beans
'''Mushroom ratio: 52%'''
Foraging quantities on grass tiles:
Aug 17: 19 skill, grass tiles only, no bushes, no trees.
bluerry 2, cabbage, carrot, cocoa bean 8, corn 4, cotton 7, cucumber 4, egg 5, hops 7, ivy 6, lettuce 3, lingonberry 9, onion, pea pod 6, potato 6, pumpkin 11, raspberry 7, iron rock 5, sprout 23, strawberry 6, sugar beet 2, tomato 2, '''wemp plants 10'''
'''Mushroom ratio: 0%'''
I'll update this further after a few more runs of tracking results, but these are completely in line with all my other foraging results thus far