A backcast of the nodes ILLINOIS.HUB and AMIL.BGS6 is as follows:

YEAR MONTH rawbasis solarweightedbasis
2018 1 -1.63 -0.88
2018 2 -0.29 -0.13
2018 3 -0.63 -0.50
2018 4 1.38 1.56
2018 5 1.04 1.48
2018 6 0.35 0.55
2018 7 0.29 0.40
2018 8 0.54 0.73
2018 9 -0.81 -0.58
2018 10 -0.20 -0.14
2018 11 -0.28 -0.12
2018 12 -0.41 -0.27
2019 1 0.31 0.48
2019 2 0.19 0.29
2019 3 -0.53 -0.50
2019 4 -0.03 -0.04
2019 5 -0.46 -0.47
2019 6 -0.05 0.00
2019 7 0.40 0.52
2019 8 0.15 0.31
2019 9 0.12 0.25
2019 10 0.37 0.57
2019 11 -0.79 -0.43
2019 12 0.18 0.55
2020 1 0.63 0.87
2020 2 0.12 0.42
2020 3 0.06 0.07
2020 4 0.07 0.25
2020 5 0.04 0.04
2020 6 0.37 0.47
2020 7 0.53 0.64
2020 8 0.33 0.40
2020 9 0.18 0.18
2020 10 -0.88 -1.21
2020 11 -2.14 -2.01
2020 12 0.35 0.27
2021 1 0.49 0.26
2021 2 3.82 3.54
2021 3 -0.37 -0.33
2021 4 0.37 0.60
2021 5 0.19 0.12