The slope isn't exaggerated at all, the increments are same as if you showed the full graph from zero. But zero isn't a useful baseline, and zooming out to fit it into your screen would give a false impression of a flat change at the top of a narrow section of history. What would fix that is a longer x-axis showing further back in time. Then you'd see a relatively flat line with some rises and dips, then at the end a sudden spike.