Answer:
a)
Year CPI Nominal Wage (dollars)
2011 211.7 $78,520
2012 213.5 = (213.5/211.7) x $78,520 = $79,187.62
2013 223.8 = (223.8/211.7) x $78,520 = $83,007.92
2014 221.1 = (221.1/211.7) x $78,520 = $82,006.48
b) if you annual wage in 2014 was $82,920, it would be equivalent to (211.7/221.1) x $82,920 = $79,394.68 in 2011.
The CPI can be used to calculate equivalent dollars and works both ways, to determine past or future equivalencies.