It's important to recognize that this is a national chart; it reflects supply over the whole country. The first of the troughs was obviously immediately after the shutdown of NRU. The second trough was caused by the planned one-month shutdown in August of the Petten reactor. We actually were surprised, when we looked at the data retrospectively, that we had quite a good supply. Our forecasts had been a little bit less than this leading into that period.
The third period of shutdown was partly related to a quality issue coming out of Petten. Part of it was due to the Air France pilot who refused to take the radioactive supply on his plane.
It's important to recognize that this is an international supply chain and we're dealing with five or six reactors around the world. So in that type of environment there are going to be areas where there is plenty of supply. For example, the BRE reactor spends 40% of its time producing isotopes and 60% of its time on research. One of the reasons the trough in August was low was that they opened up their production capacity to help support the community when Petten was down. So part of it is that it's like any commodity that is internationally produced and internationally supplied.
In terms of efficiencies, I think it's fair to say that we have learned how to use our generators a little more efficiently. We have learned how to ensure that we extract the maximum amount of radioactivity from the generators at a time when they are most radioactive and have the most medical isotope in them. I think those will carry forward. I think we have learned some lessons on how to use our generators more effectively and how to ensure that our patient flow is better.
As in any crisis, I think there are opportunities to improve process, and we have done that. I think we've probably improved our use of generators to the maximum level that we're likely to be able to.