Fig. 4

Analysis of the ethnic groups of the pulmonary cases with whom cases notified during 2009–11 were clustered retrospectively. a Proportions of cases in each ethnic group who were retrospectively clustered with pulmonary cases in other ethnic groups. b Retrospective clustering ratio for cases in each ethnic group, with 95% confidence intervals in parentheses. Dashes indicate ratios for which the ratio was zero and confidence intervals could not be calculated using the bootstrapping approach. See the caption to Fig. 3 for the interpretation of the colour coding