Complex sentence: Using online reservation data from July 2010 to October 2010, they concluded that an upgrade from 3.5 to 4 stars caused an increase of 19 percentage points, in the sellout rate for 7pm bookings.
Split into simpler sentences: Using online reservation data from July 2010 to October 2010. They concluded that an upgrade from 3.5 to 4 stars caused an increase of 19 percentage points, in the sellout rate for 7pm bookings.