Why would that matter? PV and storage costs change very rapidly, so going even five years into the past would be very misleading.

If they can change rapidly how can you confidently assert the peak was this year?

Because coal use was increasing before this year, but the increase was very small this year. So, continued rapid installation of solar/wind/storage will likely lead to a decline in coal use next year.

What, you think continued rapid decrease in cost of solar and storage will somehow make this not happen?