Your code fails to address this --> There are no fractions of people. At the end of each year, the population count is an integer: 252.8 people round down to 252 persons.

Please write in english. Look at the initial code:

function abbrevName(name){

    // code away

}

Don't use other function's name, the tests won't find it. And mark your post as having spoiler content next time, please.