OTTAWA -- The government of Alberta is being lambasted in a review of Canada's justice system as the only province to keep secret the number of Indigenous people it has locked up over the last five years.

The criticism comes as part of an annual report card released Monday by the Macdonald-Laurier Institute that ranks the provinces and territories in terms of access to justice, efficiency, cost, public safety and support for victims.

Alberta is the only province that doesn't make public its disproportionately high Indigenous incarceration rate, said report co-author Benjamin Perrin.

"It's unconscionable to keep secret the number of Indigenous people who are being sent to jail in that province every year," said Perrin, who is a law professor at the University of British Columbia in Vancouver.

"We flagged this as a problem in our first report in the fall of 2016. We expected (Alberta) would start giving this data, but it hasn't."

Alberta's Justice Department said in a statement late Monday that it missed last year's Statistics Canada deadline because of a software turnover and would provide the information moving forward.

"Due to the transition to the new system, gaps in reporting (including indigenous-related data) occurred," the statement said. "This was communicated to Statistics Canada and other agencies and is reflected in footnotes in reporting documents where appropriate."

But Perrin said the explanation is "a bit like 'the dog ate my homework' kind of excuse."

"This comes at a time of very serious concern about the treatment of Indigenous people by the justice system. People have a right to know," he said.

While Indigenous incarceration rates are disproportionately high everywhere in Canada, they are especially high in Alberta, B.C., Ontario, Saskatchewan and Manitoba, the report noted.

The overall justice system received a mixed grade in Monday's assessment, following last year's inaugural review, which concluded the country suffered from a large and growing "justice deficit."

The 2017 report card celebrated a notable drop in crime rates and a boost in legal aid funding relative to the previous year, but those improvements were overshadowed by a spike in costs, lengthier court delays and the persistent over-representation of Indigenous people in prisons.

The Ottawa-based think tank called for more data collection and monitoring by Statistics Canada to better identify and track problems that have, for too long, gone unacknowledged or unaddressed.

The assessment called for additional research into how Canadians view the police, courts and justice system at large, as well as more information on victims of crime, including referral rates for victim services.

Perrin also pointed to the need for more analysis of recidivism rates and the number of criminal cases that are stayed due to unreasonable delay.

"By arming governments, police, courts and the public with this data, we hope that it can support better decision-making and law-reform efforts," he said.

The 2017 analysis dubbed Ontario the most improved jurisdiction after it rose to fourth place from seventh, while Quebec and British Columbia each dropped two rankings.

Prince Edward Island continued to lead the pack, while Manitoba remained the lowest-ranked province, thanks in part to having one of the lowest victim restitution rates in the country and the highest proportion of accused offenders on remand while awaiting trial.

The report also found a "shockingly high" rate of violent crime in the territories -- in some cases 10 times greater than their provincial counterparts, a situation Perrin described as "dire."

The assessment highlighted some areas of improvement, noting that, between 2016 and 2017, Canada as a whole saw a slight drop in crime rates, fewer police officers required per capita and rising support for legal aid.

Among the many differences identified between various jurisdictions, a much higher proportion of accused people were found to be unlawfully at large in Quebec and Prince Edward Island compared with Nunavut, New Brunswick, or Ontario.

Public confidence in the justice system and the courts were found to be lowest in Manitoba, B.C. and Quebec and highest in New Brunswick and Ontario. As for public confidence in police, the highest levels were observed in Saskatchewan, New Brunswick and Newfoundland and Labrador, and lowest in Prince Edward Island, B.C. and Quebec.

While the rates of police solving non-violent crimes has declined in most parts of the country over the last five years, B.C. earned the distinction of having the lowest rates of resolving both violent and non-violent crimes, at about 52 per cent and 20 per cent respectively.

The federal justice department did not immediately respond to a request for comment.