Mr Kateb said the steep export drop was revealed in a parliament report by Oil Minister Rostam Qasemi.
BBC: Iranian oil revenues 'drop 45%' because of sanctions
2.
Gholam Reza Kateb, an MP on the national planning and budget committee, said the country's economy as a whole was in trouble.
BBC: Iranian oil revenues 'drop 45%' because of sanctions
3.
"On the basis of the report, oil sales are down 40% and income has dropped 45% in the last nine months, " Mr Kateb told the semi-official Isna news agency.
BBC: Iranian oil revenues 'drop 45%' because of sanctions