I believe that the first column figure (2019B) is a present figure readily available from the client in the case practice. As such, the figure can supposedly be requested. The sales volume figures at the following years are estimated values, this can either be a result of client's internal projection, or we can take a growth assumption on mobile segment sales compared to the overall parking market should we need to estimate it ourselves.
If you take a look, the present value of mobile segment sales volume is 2.5% of the total market. By assuming that the mobile market share will increase by a multiples factor between 1.5 to 2 and the total market size remains stable, then the figure would increase to 5% in 2020, 10% in 2021, 15% in 2022, 25% in 2023.
From here, we take similar percentage amount above for Parking-App share as a fraction of the mobile segment market, reflecting similar growth rate. Hence on 2020, the Parking-App share is at 2.5% of the mobile market, while it is projected to grow to 5% and 10% of mobile market in 2021 and 2022 respectively.
Finally, for the last row, we take the 10% commission share figure from Exhibit 1 to come up with the numbers.
Hope it helps.