The graph looks to be the number of deaths per month versus the calendar month. The total number of deaths would be the area under the curve— the number of deaths from cancer/heart disease are far greater than COVID19. When this is all said and done, I think a study of the number of excess deaths in 2020 would be fascinating. That would reveal if there was misreporting of the number of COVID19 deaths (either over-reporting or under-reporting).
CV deaths will be (and are) over reported.