It's not that simple. The price of electricity has changed quite a bit during the lifetime of this light. To get an accurate cost you would have to go through 77 years of electrical bills and calculate the cost for each month. Then use that to get an average cost.

My own uneducated guess is the cost is quite a bit less than the current estimates. I do know that in some places in the 1930s you paid a flat rate for electricity - and in others, electricity was part of the rent. Either (or both) of these would make the calculation even more difficult.

Then, there was a time when the cost was justified - so, if you are looking to get a cost of how much was wasted by having this light on when it was behind a wall, you would need to subtract the cost during that time.

BTW, My city fire dept has an incandescent light bulb on display that was on for over 100 years. It was installed when they built the original fire house, and still working when they tore it down. They know it was on the entire time - less power failures, as there was no light switch for it.