Answer:
Return for next 5 year = 12.49%
Explanation:
N = number of forward years
T = number of past years
Blume's formula = ((Next n years - 1)/ Past T years - 1) * Geometric return + (N-T)/(N-1)* Arithmetic Average
Return for next 5 year = (5-1/12-1) * 0.123 + (12-5/12-1) * 0.126
Return for next 5 year = (4/11) * 0.123 + (7/11) * 0.126
Return for next 5 year = 0.04473 + 0.08018
Return for next 5 year = 0.12491
Return for next 5 year = 12.49%