Empty seats at most venues have been a problem from the start with many Brazilians staying away from the Olympics and organisers failing to solve the problem on time.
Rio Games spokesman Mario Andrada said 280,000 tickets were given away to school children as part of a social project to get them to attend sports that are less popular in Brazil, but half of those were never used.
A total of about 6.1 million tickets were issued for the event.
"From the general public 11 percent did not show up," Andrada told reporters. "Even the public who bought tickets outside the door (of venues), of them seven percent did not show up at the venues."
"That confirms a suggestion that we had, that people were buying tickets to get into the (Olympic) park, not necessarily focused on a given venue."
But the biggest no-show came from the school kids, who stayed away in large numbers.
"The social programme, which distributed a lot of tickets, what we got was 55 percent of those who got free tickets did not show up. The reason, in this case, is the fact that kids are on holiday."
He said there was no central point for children to gather and be transported to the venues.
"We kind of left this a little to each family and in some cases to an NGO (non-governmental organisation)," Andrada said.
While organisers have said they exceeded their financial target from ticket sales, the low turnout, even at the athletics events, has been one of several major headaches they encountered at the Olympics, along with security, transportation and venue problems.
Sales for the Paralympics are even worse at just 12 percent of tickets sold, with the mayor of Rio unable to buy a chunk of tickets as planned due to electoral regulations.
"As we all know, the mayor had committed to buy a number of tickets. However, electoral justice prevented him from buying those tickets, so the tickets were returned to the pot and the number (of sold tickets) has decreased," Andrada said.
