Complex sentence: The 2007 a survey conducted by the American Federation of Teachers (AFT) reported that the average salary for an American teacher was $51,009; this is also recorded as the first time in history the average pay for teachers has exceeded the $50,000 mark.
Split into simpler sentences: The 2007 a survey conducted by the American Federation of Teachers (also known as the AFT) reported that the average salary for an American Teacher was $51,009. This is also recorded as the first time in history the average pay for teachers has exceeded the $50,000 mark.