Hello everyone, I guess you can call me a noob when it comes to statistics

Column A is named "age", so there are age values in it, ranging from ca. 20 to 80. Column B is named "symptoms" and there are 0 and 1 values in it (NO or YES, because the patient either has that symptom or not).

Now, it is easy to create a scatter plot with a linear trendline, however, I don't want to be linear because the dependence isn't linear. Logarithmic, polynomial etc. trendlines don't really work.

What I get is something like this:
prob.jpg

What I want to get is something like this:
img2chf2.gifChance for some critical illness at various ages before age 75 (smokers_non-smokers together).png

Thanks!