As of the latest 2007 population census conducted by the Ethiopian national statistics authorities, Addis Ababa has a total population of 2,739,551 urban and rural inhabitants. For the capital city 662,728 households were counted living in 628,984 housing units, which results in an average of 5.3 persons to a household. Although all Ethiopian ethnic groups are represented in Addis Ababa because it is the capital of the country, the largest groups include the Amhara (ethnicity) (67.04%), Oromo people (19.00%), Gurage (16.34%), Tigrayans (5.18%), Silte people (2.94%), and Gamo people (1.68%). Languages spoken include Amharic language (71.0%), Oromo language (10.7%), Gurage language (8.37%), Tigrinya language (3.60%), Silte language (1.82%) and Gamo language (1.03%). The religion with the most believers in Addis Ababa is Ethiopian Orthodox Tewahido Church with 74.7% of the population, while 16.2% are Islam in Ethiopia, 7.77% Pentay, and 0.48% Roman Catholicism in Ethiopia.
Question: How many percent do the Gamo, Silte and Tigrayans ethnicities make combined?
Answer: 9.8