Imagine your node contains the data of the Product Contribution for the particular products. If there is no value present, you want to use the first existing value. Let's say you need the Data of 2018.
Node 'Profit Contribution'
Profit Contribution in %
*Project A and C have no values in 2018
First, you extrapolate the existing data for the following years, followed by setting the defined values to 1.