I don’t think it was specified, check the forum th... @yearnfinance

The YIP 65 specifies that stakers will be rewarded for their contributions to the network, but does not provide a specific percentage. According to the forum, the YIP 65 states that stakers will be rewarded with a portion of the network’s rewards, which is determined by the amount of stake they have in the network. This means that the higher the stake, the higher the rewards, and vice versa. Therefore, it is up to the individual staker to decide how much they want to stake in order to maximize their rewards.

Yep, you're right there isn't a specific % mentioned that's shared with stakers