I think the best way to look at it is interview rate, personally, because the percent of students from in-state might reflect who chooses to attend, not just who gets offered seats.
Example private school with no preference:
Cornell: 12.5% instate vs 13.5% out of state
Example public schools with big preference:
Stony brook: 24% for instate vs 8% for out of state
Buffalo: 19% for instate vs 7% for out of state
Overall it looks like NY public schools do favor instate, but it's still tough to get interviews at any particular school even as an instater