What are the lines in this Solar Cycle graph?
In the above plot by Hathaway,
the jagged line peaking at 284.5 in June 1989
is the monthly international sunspot number.
The smooth curve starting and ending a few years later is a
prediction
based on recent observations and statistics of past cycles.

The peak of 212.5 in November 1989 is for a
13-month smoothing
of the monthly number.
The Sunspot Index and Long-term Solar Observations (SILSO)
project at the Royal Observatory of Belgium
archives
these data and provides
this plot
of the monthly and smoothed sunspot numbers together.