The more complete answer is that it depends. When commercial milk is mixed, it tends to come to an average of about 6.68. Raw milk when mixed from a large herd tends to be around 6.7. This is when fresh. But, there are seasonal variabilities even when large amounts of milk are mixed.
When dealing with smaller volumes, or individual animals, there can be significant variability based on health, feed, seasonality, stress, etc.
Bulk milk = averaged values = generally more consistency in fresh milk
Farmstead milk = depends on feed, health, etc because of fewer animals.