Histogram with incomplete data

I am trying to show a histogram of time to failure for a population of fielded systems.  I need two metrics:  1)  the total failure rate as a function of time (allowing that the systems are repairable and that some experience multiple failures; and 2) the failed system rate (counting only the first failure for each system).

Unfortunately, the data are incomplete--I know how many systems have been fielded, and how many experienced a failure, but I only have time data for about 2/3 of the failures.  

In Excel I would create the bins, bin the failures with data, calculate the bin percentages and multiply the percentages by the absolute failure rate for the total population to get an assumed rate at each bin (the assumption being that the time distribution for reported events and nonreported events is the same).  I don't know how to do that in BI.  Alternately, I could show a histogram column for 'no data', but I don't know how to do that either. 

I built a siimplified sample dataset, but I don't see a way to post PBIX files to the forum.  The histograms appear to correctly calculate the bins for the failures with data, but they do not extrapolate to cover the holes.

Any suggestions?