I will let NorthOntKid do his own calculations. Since he just became a member I'm always leary of intent. Here is what the award judgement says:

As a result of the Respondent's breaches of the BIT, the Respondent shall pay to the Claimant damages amounting to US$ 1,202 million (one thousand two hundred and two million United States Dollars);

The Respondent is ordered to pay pre-award interest on the amount specified in subparagraph (d) above at the rate of the 6-month average U.S. Dollar LIBOR + 1%, compounded annually, calculated from 13 April 2008 until the date of the Award;

The Respondent is ordered to pay post-award interest on the amounts specified in subparagraph (d) and (e) above at the rate of the 6-month average U.S. Dollar LIBOR + 1%, compounded annually, calculated from the date of the Award until full payment; 

Anyone who wants to read the award judgement can do so at:

https://www.italaw.com/sites/default/files/case-documents/italaw7194.pdf