How to find data using nonlinear curve-fitting?

I have a curve which is from a paper. The curve is as follows:

Although the values of x-axis are shown on this graph, but the values of y-axis are undetermined and I need to find them. The only extra information that I have is the area between the curve and the dashed line which has been reported in the paper. I extracted the graph data using webplotdigitizer assuming y-data are changing from 0-1. By having the area (area= 25.56) I need to find y-data. Can anyone help me how can I find y-data? The extracted data using webplotdigitizer are attached.