The last bar presents the total of all of them, any graph should be carefully observed and read the data, not just looking at the colors.

But if this is the norm (I don't know) when I publish the finished graphic, I will remove the totals bar.
thx
edit:

that's better?
Nice graph.
That being said, I think the number of hacked exchanges per year is not taking into account the increase in number of exchanges. It would seem that security/risks is getting worse, when maybe it is the contrary. I would suggest to compare the figure of "hacked exchanged / total number of exchanges active in that year". That would probably give a better overall view of how security is progressing. And show how in the first years probably there were even more hacks than exchanges active (repeated hacks).