If the consumer price index for a sample of goods and services purchased in Dallas rose from 100 at the end of 1967 to x at the end of 1985, what was the average Q(arithmetic mean) annual increase in the index over this period?	Choose the correct answer:
A) (x + 100)/18 B) x/18 C) (100 − x)/18 D) (x − 100)/18 E) 100x/18
CPI in end of 1967 = 100   CPI in end of 1985 = x   Number of years = 18   Average annual increase in CPI Q= (x-100)/18   Answer (x − 100)/18
<result>D</result>
If the consumer price index for a sample of goods and services purchased in Dallas rose from 100 at the end of 1967 to x at the end of 1985, what was the average Q(arithmetic mean) annual increase in the index over this period?