The Bamako-Sénou International Airport is  from the city and opened to passengers in 1974. Passenger traffic steadily increased in the early 2000s. Government figures revealed 403,380 passengers in 1999, 423,506 in 2003, 486,526 in 2004, and 516,000 in 2005, and is predicted to reach over 900,000 by 2015 under a low (4%) yearly growth-rate scenario. To date this growth rate has been surpassed. Total air traffic the airport increased by 12.4% in 2007 and 14% in 2008. Most of this increase came in passenger transport, with the number of passengers served increasing by 20% in 2007 and 17% in 2008. Twenty-seven airline carriers operated weekly or better at Bamako-Sénou International Airport in the 2007-2008 period. This continued growth was offset by cargo flights decline of 16.75% in 2007, and 3.93% in 2008. The highest frequency route is on the Bamako-Dakar sector with 29 weekly non-stop connections. Domestic flights also serve Malis regional capitals Kayes, Mopti, Timbuktu, Sikasso, Gao, and Kidal. Bamako Senou International Airport is managed by Aéroports du Mali (ADM). Its operations are overseen by the Malian Ministry of Equipment and Transports.
Question: How many percentage points did the airport traffic increase by between 2007 and 2008?
Answer: 26.4