The line graph illustrates the number of reported cases of X disease in Someland between 1960 and 1995.
Overall, the incidence of this disease rose dramatically until the late 1970s before falling sharply to zero by 1990, where it remained stable afterward.
In detail, there were only about 100 cases in 1960, and the figure stayed almost unchanged until 1965. However, between 1965 and 1975, the number of cases increased significantly from roughly 100 to 500. The situation remained steady for the next five years, with the incidence holding constant at its peak of around 500 cases in 1980.
After 1980, the number of cases began to decline considerably, dropping to around 350 in 1985 and then falling abruptly to none by 1990. From that point onward, no further cases were recorded until 1995.