Lifetime vs. maximum BP diameter. A total of 656 BPs are used. A power law with the form y = ατ^β, where α = 7.72 ± 0.87 and β = 0.129 ± 0.011, is shown in red, and the grey background shows the 3σ confidence level. The root-mean-square error for the fit is 9.7. The average maximum BP diameter for each lifetime bin is shown as a white circle, with the standard deviation as the error.