Oh and here is a power spectrum for periodicity - looks like some relevant peaks at 163 and 175 days:
I used Mathematica to create this.
I pasted the 893 numbers into input[1] in a notebook, and the output labeled each as Out[1], Out[2], ...
Then I did
Price = Table[Out[k], {k, 1, 893}];
FFTPrice = Abs[Fourier[Price]]^2;
Length[FFTPrice]
returned
Then drop half of it (it's symmetrical and half is a copy...useless)
FFTHALF = Drop[FFTPrice, -446];
ListLinePlot[FFTHALF, ImageSize -> 1400, PlotRange -> {0, 12000}]