A group of 100 Seattle school children who lacked antibodies to measles (i.e., were not immune to measles) were followed for a total of 154 person-months for infection with measles. At the end of the follow-up, 30 children had acquired antibody to measles.
At the end of the follow up period, what was the prevalence of measles antibody among the school children (per 100), round to two decimal places if applicable?