Résumé:
The main purpose of the present study is to evaluate the size of informal economy in Algeria using the simple currency ratio method of Gutmann, Thus we started this research paper with analyzing the ratio of currency in circulation to the demand deposits in Algeria during the period 1990-2017. The empirical results pointed out that the ratio of informal economy to official economy reached around the value of 25 to 30 % during the period of 1990-2003 and follows a decreasing trend during the period 2001-2007. And the general graph trend From 2008 to 2016 seemed increasing to about 25% of the official GDP by the end of 2016.