Henri J. Gouchon, Honorific President of the "International Center of Astrology", has introduced for the first time the notion of "Slow Planets Concentration Factor".
This factor is very simple to establish and consists to measure the angular distance including all the slow planets (from Jupiter to Pluto).

André Barbault has developed this notion in his book "The Experimental Prognostic in Astrology" (ed Payot, Paris, 1973) and showed an amazing correlation between the period of "positive economical periods" (slow planets are expanding), "negative economical periods" (slow planets are gathering), "best economical periods" (maxima of the curve) and "worst economical periods" which have led in certain cases to "world wars" (minima of the curve).

We have recalculated that curve very precisely for the period covering 1900 to 2050 as presented here under. It is remarkable to see the similarity between that curve and the major world political and economical events of the 20th Century !
It is also to note that a new small crise is forecasted from 2003 up to 2011 and another deeper from 2014 to 2020.