The number of criminal charges heard in WA courts continues to fall, with Children's Court cases dropping 20 per cent in the past financial year.
Australian Bureau of Statistics figures released last week also revealed 92 per cent of defendants in WA in the 2011-12 financial year were found guilty.
Of those, 7.3 per cent received custodial sentences, an increase from 6.3 per cent in 2010-11.
The figures revealed that minor offences continued to place the most pressure on the State's court system, with traffic offences accounting for almost 50 per cent of cases in magistrates' courts.
In 2011-12, 78,331 cases were heard in magistrates' courts, a fall of 11 per cent on the previous year.
The number of charges in the Children's Court fell 20 per cent to 5804, with traffic offences accounting for most cases followed by theft, stealing and acts intended to cause injury.
In the Supreme and District courts, 89 per cent of those found guilty were sentenced to custodial orders, which include jail terms, juvenile detention, intensive corrections orders in the community and suspended jail terms.
Most of the charges heard in the higher courts involved illicit drug offences, followed by sexual assault and unlawful entry.
Nationwide, 6 per cent of defendants found guilty were sent to prison, a 3 per cent increase compared with 2010-11.
ABS director of the National Centre for Crime and Justice Statistics Fiona Dowsley said traffic offences continued to dominate the courts' workloads in 2011-12, with 41 per cent of defendants appearing for traffic or motor vehicle offences.
Criminal Lawyers' Association of WA president Linda Black said she was not surprised by the fall in cases before magistrates' courts.
"There is a much more efficient and robust system where charges are looked at closely and approached in a very methodical way," Ms Black said. She said police prosecutors and the office of the Director of Public Prosecutions had also become more ruthless in examining the appropriateness of matters proceeding to trial.