Observed and expected exclusion limits for a Standard Model Higgs boson at the 95-percent confidence level for the combined CDF and DZero analyses. The limits are expressed as multiples of the SM prediction for test masses chosen every 5 GeV/c² in the range of 100 to 200 GeV/c². The points are joined by straight lines for better readability. The yellow and green bands indicate the 68- and 95-percent probability regions, in the absence of a signal. The CDF and DZero data exclude a Higgs boson between 158 and 175 GeV/c² at the 95-percent confidence level and show that the Tevatron experiments are beginning to be sensitive to a low-mass Higgs boson.