Fewer thefts, arsons and rapes here helped bring Illinois’ crime rate down in 2005, but a majority of the state’s communities reported a rise in serious crime, according to Illinois State Police data.

Law enforcement officials in Illinois reported 473,834 serious crimes in 2005, resulting in a 3.1 percent decline in the state’s crime rate, according to information provided by state police that will be released Sunday.

That’s 37.3 crimes per 1,000 people, which is down from 38.3 per 1,000 in 2004.

Fifty-four counties reported an increased number of crimes, while 46 reported fewer crimes and two reported no change.

Chicago’s overall crime rate, which accounts for a little over 35 percent of the state’s reported crime figures, decreased 6.5 percent. Suburban Cook County’s overall crime rate decreased 4.2 percent and the collar counties saw a 1.4 percent decrease.

The city and its immediate neighbors reported disparate trends in violent crime.

Chicago saw decreases in assaults and rapes that resulted in a 2.8 percent drop in violent crime, while suburban Cook County reported a 10.6 percent increase in violent crime and Chicago’s collar counties reported a 4.4 percent increase.

“There’s the Chicago pattern and the elsewhere pattern,” said Wesley Skogan, a Northwestern University criminologist. “Around the country there is a perception that city crime rates, especially mid-city crime rates, are going up substantially.”

The lion’s share of crimes reported in Illinois were property crimes, which include burglary, theft and arson. There 401,607 of them reported in 2005, or 13,720 fewer than 2004. That’s a decrease of 3.3 percent.

Police around the state, meanwhile, reported a total of 72,227 violent crimes in 2005, an increase of 1,085 from the year before, or 1.5 percent. Violent crime includes murders, criminal sexual assaults and robberies.

There were 766 murders in Illinois in 2005, 14 fewer than the year before, a decrease of 1.8 percent.

Regionally, crime in southern Illinois rose three percent. Clinton, Perry and Randolph counties were among the areas reporting a spike in crime, according to the data.

Central Illinois, meanwhile, saw a 14 percent increase. There was a 5.7 percent increase in the amount of serious crime reported in Champaign County, an 8.9 percent in Peoria County and a 6.2 percent rise in Sangamon County.

Northern Illinois, excluding Cook County, reported a .6 percent decrease in serious crime.

State police say the production and use of methamphetamine is the cause of much of the crime in southern and central Illinois.

Several response teams formed in May 2005 to fight the spread of meth reported earlier this summer that they had handled 750 meth-related incidents.

“The Illinois State Police will continue to dedicate all the resources necessary to combat the proliferation of this dangerous and devastating drug,” State Police Director Larry G. Trent said.

The efforts appear to be resulting in more arrests. An increase in drug-related arrests were reported in some of largest counties in southern and central Illinois: Madison, Peoria, Sangamon and St. Clair.

“Meth is a drug that really causes a lot of extreme, erratic and out of control behavior, so people under the influence of meth are more likely to engage in violence and contribute to disorder in a community,” said Arthur Lurigio, a psychologist and criminal justice professor at Loyola University of Chicago.