It's from October 3, 2007 PRMO PR. I also done some interesting calculation as follow:
50 kg per week x 52 week per year x 2 years = 5200kg.
According to PRMO financial report, the inventory was 5000kg by December 2008.
I understand that PRMO started production in early 2007. Say, after 2 years production, the inventory should be roughly 5000kg, based on the above calculation.
The inventory was increased to 6100kg by June 2009. Half a year production is roughly 1100kg.
5000kg + 1100kg = 6100kg BINGO