United’s hopes of securing a lucrative top-four finish took a blow on Wednesday after they drew 0-0 with Hull City at Old Trafford.
The result means United have now drawn more Premier League home games this season (6) than they have won (5) and they have managed just 17 goals in their 12 matches at Old Trafford.
United have been significantly outscored by all of their top-six rivals and Mourinho admits he is frustrated by his side’s inability to convert territory and possession into goals.
“I have to agree with you that we don’t score enough goals,” said Mourinho. “Some of our players from these attacking creative positions they could – they should – score more goals.
“I understand what you are saying. We attack so much and with so many players, and so many players have the freedom in our dynamic to reach scoring positions.
“When you see the number of goals we score, there is not a true relation between our attacking production and the number of payers we put in attacking positions and the number of goals we score.”
Ibrahimovic, at 35 years old, is comfortably United’s top scorer with 19 goals, 14 of which have come in the league.