Native American state tax exemption

My wife is a member of the Luiseno Indian Tribe in southern California, and we live in Colorado (not on the reservation, obviously). They receive a small amount of money each year which is reported on a 1099-MISC. I have included that in our federal tax return and am now looking at the state tax forms for Colorado. In the Miscellaneous section is a Native American Indian Reservation Income field which is labeled Income Earned on the Reservation. Do I leave this empty since we do not live on the reservation? It's confusing because the income is directly for tribal membership.

Thank you.