What you need is consumption in constan price of 1999-2000 which can be estimated with current consumption devided by Consuption Price Index (CPI). 

For your seco

Article Price and Income Elasticities of Gasoline Demand in Iran: Us...

For your second questin, firstly the constan consumption of base year (X) must be multiplied by the CPI of the correspondin year (X). Then the results must be devided by the CPI of 1999-2000.

Thanks Dear Vahid

Can we used GDP deflator instead of CPI

Regards

irshad

Yes. However, CPI is more common in this case. Obviously, it depends on your study suject. CPI is based on a special basket or portfolio of goods but GDP deflator is

OK thanks

Is a welcome development

Ok thanks Dear ALam Khan

i want it to be in 2000 prices. please guide me if i divide it with CPI with constant 2000 prices it ok or not

regards

irshad

ok thanks