Consider considering the following data on HIV seroconversion from negative to positive and a high risk group of 2000 subjects from January 1, 2015 to December 31, 2017 assume that HIV positivity is permanent and there are no entries to or losses from the group of subjects on January 1, 2015, there are 160 positive seroconversions on January 1, 2016 there are 150 positive seroconversions and on January 1, 2017 there are 175 positive cereal conversions on January 1, 2017 there are 175 positive seroconversions. Calculate the incidence rate in 2016 and calculate the three year incidence rate from 2015 to 2017 from 2015 to 2017