Yearly Production - Total Per Organization Number

I am attempting to sum the gas production for each organization number, and separate gas production into each year as such:

Organization_Number20082009201020112012
103 774 7313868470

But currently I am having trouble displaying this, and it's coming out as such:

Organization_NumberMonth20082009201020112012
103 1 774731386847NULL
103 2 810656654674NULL
202 1 27262702293725122048
202 2 2913205120202064NULL

I want to remove the month and have one total per organization number, as well as remove NULL as show as 0.

Code:
select *
from yearproduction
pivot(
sum(Gas_Prod)
for Year in ([2008], [2009], [2010], [2011], [2012]))
as YearlyProduction
order by Organization_Number, Month