Seasonal index, month by month
The peaks and troughs average out to 1.00 across the year
  Each month’s index   The flat figure, 1.00
Tap or hover a bar for that month’s index and dollar figure.
July runs 1.50 times the flat figure, October 0.51 times.
Source: seasonal-index method from an open statistics textbook; monthly shape from the modeled $2M HVAC year (Steph’s Books), illustrative. Flat figure: $166,667 a month.