The immigrant population (those with two foreign-born parents) in Bergen, includes 42,169 individuals with backgrounds from 180 countries representing 15.5% of the citys population (2014). Of these, 50.2% have background from Europe, 28.9% from Asia, 13.1% from Africa, 5.5% from Latin America, 1.9% from North America, and 0.4% from Oceania. The immigrant population in Bergen in the period 1993-2008 increased by 119.7%, while the ethnic Norwegian population grew by 8.1% during the same period. The national average is 138.0% and 4.2%. The immigrant population has thus accounted for 43.6% of Bergens population growth and 60.8% of Norways population growth during the period 1993-2008, compared with 84.5% in Oslo.
Question: How many years is the time span where the immigrant population in Bergen increased 119.7%?
Answer: 15