Gamma Ray Burst Frequency vs Energy?

Not more energy than the observable universe - the total isotropic energy of a GRB if it did explode that way would be about 10^54 ergs, or equal to about 1000 Suns being completely converted to energy at once. Unreasonable, but definitely not more energy than the universe has. The typical jet opening angle of a GRB is in the 3-6 degree range, and there are two jets. To solve the first problem, you'd have to figure out how much of a complete sphere that is - what percentage of an isotropic sphere would we be seeing - and use that to determine what percentage of GRBs we're missing. Also, the detection rate is closer to 2 per week, and the satellite detecting most of them (Swift) only have a 1/6 of the sky field of view at any one time, so you'd have to take that into account as well.