ANNUAL TURNOVER

In which year turnover shall be considered?
is it consider in agreement year,or services provided year,or payment received year.

Example
There is works contract.
In current year we received one contract for the amount of rs 20,00,000.
such contract we received in next two years.
in first year we completed and received payment of rs.10,00,000
and in next year 10,00,000
then this both 10,00,000 is considered in current year or in the respective years.
please answer it .