Sunspots are dark marks on the sun's surface which can affect things on Earth such as radio signals. The number of sunspots recorded monthly from 1965 – 2020 is shown in the time series graph below. Estimate the year when the most sunspots were recorded for 1965 – 2020 and work out an estimate for the number of sunspots in that year.

By visually inspecting the time series graph, we can identify the highest peak. This peak occurs between the years 1970 and 1990, and looks to be roughly at the halfway point, which is 1980. A more precise look shows it slightly before the 1980 mark, so an answer of late 1979 or 1980 is appropriate. To find the number of sunspots, we trace a horizontal line from this peak to the y-axis. The peak is clearly above 250 but below 300. It appears to be more than halfway up, so an estimate of 270, 280, or 290 would be reasonable. Let's estimate it as 280.