Monte Carlo analysis of the measurements of Smith et al. of the number of fission neutrons produced per neutron absorbed, η, for 2200 m/sec neutrons absorbed by 233U and 235U yields: = 2.2993 ± 0.0082 and = 2.0777 ± 0.0064. The standard deviations include Monte Carlo, cross-section, and experimental uncertainties. The Monte Carlo analysis was confirmed by calculating measured quantities used by the experimentalists in determining η2200.