After another day, I will venture a few thoughts on this. I find that many programming problems are all about taking a vague notion (like "I have a vague shape and I want to get the computer to automatically replicate something similar to that shape.") and put into something concrete so that I can tell the computer how to perform that vague task. You haven't given a lot of detail into how you chose the numbers you give, so I could be missing something here. I would expect to approach this problem something like this (still in kind of vague terms, because I cannot know what details are important to your project):

1) First, I need some way to quantify the shape of the sparklines. (Note: My version of Excel does not support sparklines, so I cannot see them, but I can see the shape of the values in columns Q:W). This is more of a maths exercise than a programming exercise. I see a "shape" that has a peak/vertex/maximum in the middle and decreasing to both sides, so I think of different shapes that I know of. Many conic sections have that kind of shape (https://www.mathsisfun.com/geometry/conic-sections.html ) and usually can be formulated by simply defining the "vertex" and the "width" of the conic. Another group of curves with that kind of shape are many of the statistical distributions (like the bell/Gaussian/normal distribution), again where I can fairly easily define the curve in terms of the maximum point and the width. I expect there are many other ways, too, depending on your exact needs.
2) Then fit my equation to the 7 year scenario to get a feel for the shape of the known case.
3) Then adjust the parameters of the equation to predict the shape of the other scenarios.
4) Fine tune and evaluate the process until I am comfortable with it.

It's still kind of vague, but that's the framework I would expect to use. A lot of the work is the pre-programming stage of figuring out how to quantify the vague notion of shape. Once you have figured out how to quantify shape, then the programming steps of fitting and adjusting can be done.