Please answer a question about the following article about Indigenous peoples of the Americas:

Native Americans in the United States make up 0.97% to 2% of the population. In the 2010 census, 2.9 million people self-identified as Native American, Native Hawaiian, and Alaska Native alone, and 5.2 million people identified as U.S. Native Americans, either alone or in combination with one or more ethnicity or other races. 1.8 million are recognized as enrolled tribal members.[citation needed] Tribes have established their own criteria for membership, which are often based on blood quantum, lineal descent, or residency. A minority of US Native Americans live in land units called Indian reservations. Some California and Southwestern tribes, such as the Kumeyaay, Cocopa, Pascua Yaqui and Apache span both sides of the US–Mexican border. Haudenosaunee people have the legal right to freely cross the US–Canadian border. Athabascan, Tlingit, Haida, Tsimshian, Iñupiat, Blackfeet, Nakota, Cree, Anishinaabe, Huron, Lenape, Mi'kmaq, Penobscot, and Haudenosaunee, among others live in both Canada and the US.

How many of the self-identified Native Americans are recognized as enrolled tribal members?
1.8 million