Extract calculated data from website with macro

Hi!

I'm new to coding and I need some help.

I've succeeded to enter values from my workbook on the website and to let the website calculate the result. Now I need to extract the result into a cell ...

The website: http://data-onderwijs.vlaanderen.be/salaris/bedrijfsvoorheffing/

If the next values are entered: 

Then the result after clicking 'Bereken' is 234,63 and that value needs to be inserted in my workbook in cell C22.

What I've got so far:

Thank you in advance!!!