Club foot is one of the most common congenital skeletal abnormalities, with a worldwide incidence of about 1 in 1000 births. Both genetic and nongenetic factors are thought to be responsible for club foot. C. A. Gurnett et al. (2008. American Journal of Human Genetics 83:616–622) identified a family in which club foot was inherited as an autosomal dominant trait with reduced penetrance. They discovered a mutation in the PITXI gene that caused club foot in this family. Through DNA testing, they determined that 11 people in the family carried the PITXI mutation, but only 8 of these people had club foot. What is the penetrance of PITXI mutation in this family? Please round to two decimal places (e. g. 0.01).