Specifically where the air traffic is coming from when flying over Sunset and Ocean Park. The studies calculate the percentage of operations coming from flight schools, training flights and jets.

58 flights (departures) during the period from 12 p.m. to 3 p.m., an average of one flight every 3.1 minutes.
60% of all traffic was flight school and training related
1 plane accounted for 30% of all flights (departures)
17 flights - N2092L (Skyward Aviation)

The study was on the 250 heading test and studied the effect of the test on IFR flights only. It excludes traffic from jets and VFR flights.

"Propeller aircraft operations for April 2011 increased 17% from the 7,509 propeller aircraft operations recorded during April 2010." Pages 1 & 2 go into detail on the type of traffic that has increased. The number of operations (take-offs and/or landings) is expected to increase as the economy continues to improve.