"[T]he PBGC believes that the new safe harbors are simpler, more flexible and easier to comply with than those provided in the proposed regulations. The PBGC anticipates that approximately 94% of plans and sponsors will be exempt from many reporting requirements under the final regulations. With the addition of the safe harbors and the shift in emphasis to a plan's risk of default, the final regulations provide pension plan sponsors with more waivers from the reporting requirements and are expected to result in a net reduction in reporting."