THE PILOT WAS CONDUCTING A SIGHTSEEING HELICOPTER TOUR AND NOTICED A FUEL PUMP CAUTION LIGHT. HE THEN NOTICED THAT THE FUEL LEVEL WAS LOW BUT DECIDED THAT SUFFICIENT FUEL WAS AVAILABLE TO COMPLETE A LANDING APPROACH TO THE DEPARTURE HELIPAD. AT ABOUT 50 FEET A.G.L. AND ABOUT 40 KNOTS OF AIRSPEED, THE ENGINE QUIT. DURING THE AUTOROTATION, THE HELICOPTER SUSTAINED A HARD LANDING, COLLAPSING THE LANDING GEAR AND THEN IMPACTING AN AIRPORT PERIMETER FENCE. ALL AVAILABLE FUEL WAS EXHAUSTED. THE HELICOPTER WAS REFUELED PRIOR TO THE THIRD DEPARTURE, OF A TOTAL OF FIVE FLIGHTS. FOLLOWING A LUNCH BREAK, THE PILOT DEPARTED ON THE ACCIDENT FLIGHT. COMPANY MANIFEST SHEETS FOR EACH FLIGHT LIST A STANDARD FUEL LOAD OF 40 OR 65 GALLONS. IN THIS ACCIDENT, THE MANIFEST SHEETS DID NOT ACCURATELY REFLECT THE ACTUAL QUANTITY OF FUEL ON BOARD FOR EACH FLIGHT. THE PILOT DID NOT VISUALLY VERIFY THE ACTUAL FUEL AMOUNT BEFORE THE ACCIDENT FLIGHT.