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

893

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}]