  We experimentally explore the phenomenon of electron tunneling across a
modulated tunneling barrier which is created between an STM tip and an Au film
deposited on a vibrating piezo surface. Measurements of the time series of the
quantum mechanical tunneling current across the modulating barrier show large
fluctuations. Analysis of the average work done in establishing tunneling
current in finite time interval shows a distribution of both positive and
negative work events. The negative work events suggest tunneling against the
bias voltage direction. We show that these distributions obey the Gallavotti
Cohen Non-equilibrium Fluctuation Relations (GC-NEFR) valid for systems driven
through a dissipating environment. Typically, while the GC-NEFR has been shown
for non -equilibrium classical systems we show its validity for the quantum
mechanical tunneling process too. The GC-NEFR analysis also gives us a way to
measure the dissipation present in this quantum tunneling system. We propose
the modulated barrier behaves like a lossy scattering medium for the tunneling
electrons resulting in a tendency to randomize of the tunneling process.
