The line graph illustrates the number of cases of X disease in Someland between 1983 and 1992.
Overall, the number of cases fluctuated significantly over the period. After remaining stable in the first three years, the figure rose steadily to 1987, before falling in 1988 and then surging to a peak in 1989. It subsequently levelled off for two years and then dropped dramatically to zero in the final year.
At the beginning of the period, there were 100 reported cases in 1983, and this figure remained unchanged in both 1984 and 1985. From that point, the number began to rise, increasing to 150 in 1986 before climbing further to 200 in 1987. This upward movement suggests a period of gradual but consistent growth after the initial stability.
However, this trend did not continue. In 1988, the figure fell back to 100, representing a noticeable decline from the previous year. This was followed by a dramatic jump to 400 in 1989, the highest level recorded on the chart. After reaching this peak, the number of cases decreased slightly to 350 in 1990 and then remained stable in 1991. In 1992, however, the figure plunged to 0, marking by far the sharpest fall shown during the period.