I found these 3 periodograms I made:

![Soim periodogram 1860-1930](https://dl.dropboxusercontent.com/u/61621163/Images/periodisoim1-1860-1930h.png)

![Soim periodogram1931-1975](https://dl.dropboxusercontent.com/u/61621163/Images/periodisoim1-1930-1976h.png)

![SoimPeriodogram 1976-2014](https://dl.dropboxusercontent.com/u/61621163/Images/periodisoim1-1976-2014h.png)

which show some changes. I'm just following the heuristics of random waving and the open source principle of publish first,think later. Good training though.