A glance at the line graph provided reveals the number of diarrhea cases in Mashhad during the period from 1983 to 1992. It can be clearly seen that the highest and lowest figures observed in 1989 and 1992, respectively.
According to the graph, in the first year of the period (1983), some cases stood at 100 and remained unchanged until 1984. Then, there was a slight increase in 1985 and that was followed by another increase, although much steeper in 1986 when cases were 200. 1987 came with a small increase again, and then trend dropped to reach 100 to the same level it was in 1983. In the following year, a number of cases witnessed rapid increase (400), but this was not to last since they dropped again in 1990. After this, figures stayed stable for one year and plunged to zero in 1992.
Overall, the figures of diarrhea cases fluctuated remarkably in the second half of period rather than first half.