This Document that I found trougth by the finder before explained, must be very useful and interesting:
Bombing the European Axis Powers
...byproducts of great value to the
German war economy. By September...Ludwigshafen plants deprived the
Germans of 63 percent of their synthetic...sent an equal amount against
tank production. High
German losses in armored fighting...Allies to conclude that the
Germans were desperately short of...the
Germans sent finished
tanks to the front within a month of completion...
http://aupress.maxwell.af.mil/Books/Davis_B99/Davis_B99.pdf