What is the average fastest lap speed for the Monaco Grand Prix in 2008?
SELECT avg(T2.fastestlapspeed) FROM races AS T1 JOIN results AS T2 ON T1.raceid = T2.raceid WHERE T1.year = 2008 AND T1.name = "Monaco Grand Prix"
2008'de Monaco Grand Prix için ortalama en hızlı tur hızı nedir?