Cumulative growth histogram

Hi All,

I just got introduced to Power BI and have been testing it out. I`ve been creating some visualisations using it.

I have a table called observations , in which I have a column called "created_on". I have charted out a bar graph of no of observations per year using this colum. However, I wish to make a histogram showing the cumulative growth over the years. I have tried googling and there seem to be may discussions on this but I just can figure out what exactly I need to do.

Please help!