Listed below are the sales at Roberta’s Ice Cream Stand for the last 5 years, 2012 through 2016.

Year.................................................... Sales
2012................................................ $130,000
2013................................................ 145,000
2014................................................ 120,000
2015................................................ 170,000
2016................................................ 190,000

a. Find the simple index for each year using 2012 as the base year.
b. Find the simple index for each year using 2012–2013 as the base year.