How many tribes are in Laos?

Laos is a multi-ethnic country with seven ethnic familiesdivided in several groups, each one with their own languages. In Laos we can find 87 different languages, while it is reported that we have 160 ethnic groups. The seven ethnic groups are Mon-Khmer, Palaungic, Khmuic, Tibeto-Burman, Hmong-Mien, Tai and Rau, Chinese and Chere & Jri, these two tribes are undefined.