  We present a method how to estimate from experimental data of a turbulent
velocity field the drift and the diffusion coefficient of a Fokker-Planck
equation. It is shown that solutions of this Fokker-Planck equation reproduce
with high accuracy the statistics of velocity increments in the inertial range.
Using solutions with different initial conditions at large scales we show that
they converge. This can be interpreted as a signature of the universality of
small scale turbulence in the limit of large inertial ranges.
