Idea borrowed from here
While the original post was done on Dow, I have done the same on Sensex. Number of data points is 7606 since the history of BSE Sensex is much smaller than Dow which has been in existence for more than a Century.
Here is the result,
Here is how it looks if plotted on daily basis
and here is the aggregate performance
PostScript: Changed the Average Monthly Performance Chart since previous one used wrong data 😦