In the following figures, smoothed is a seven day running average.
I tried fitting a cubic function to the cumulative points.
a = 7.50928e+06 +/- 1.438e+05 (1.914%) b = 8.57238e+07 +/- 9.25e+05 (1.079%) c = -2.46666e+07 +/- 1.691e+06 (6.854%) d = 8.94382e+06 +/- 8.32e+05 (9.302%)
Note - The next three graphs use a log scale.