REUTERS/Marco BelloCaracas (AFP) - President Nicolas Maduro, speaking in a national broadcast on the eve of International Workers' Day, decreed a 30 percent increase in the minimum wage for Venezuelan workers. In his late Saturday presentation Maduro also called on his followers to join May Day rallies in Caracas. While the minimum wage increase may seem substantial, given Venezuela's triple-digit inflation rate that brings the amount to the equivalent of $40 a month at the official exchange rate, or just $14 a month at the black market rate. The decree, which come into effect on Sunday, includes pay raises for public workers, pensioners and members of the military. Once-booming Venezuela, which has the world's largest proven oil reserves, has plunged into economic chaos as global crude prices have collapsed.