Crimes investigated by the Lafayette Parish’s Sheriff’s Office decreased by about 8 percent overall last year, according to 2015 crime statistics released on Thursday.

The latest crime data shows slight decreases in violent and property crimes in the unincorporated areas of the parish that are covered by the Sheriff’s Office. However, they show a significant increase in the fluctuating number of reported rapes.

Reported crimes within the Lafayette city limits also decreased last year by about 2 percent, according to Lafayette Police Department crime statistics released in February. But the city saw its homicide rate more than double in 2015, from nine the year before to 20.

Although the Sheriff’s Office is the lead law enforcement agency in Lafayette Parish, it investigates crimes in the unincorporated parts of the parish.

Reported violent crimes there decreased last year by about 6.5 percent.

The number of homicides did not change from the prior year, with six reported. That includes five cases of murder and non-negligent manslaughter and one case of negligent manslaughter.

Thirty forcible rapes were reported last year, compared with 16 in 2014. The number has shown fluctuations each year for at least the last decade, ranging from 13 to 29.

Reported forcible rapes also nearly doubled this year within the city limits of Lafayette, at 19 in 2015 compared with 10 the year before — although the city’s number also has shown up and down fluctuations over the years.

Assaults investigated by the Sheriff’s Office decreased by about 8.5 percent, from 1,087 to 995. Most of those cases involved simple assault, with 755 of the cases involving no weapon.

Sixty-one of the assaults involved a firearm, while 147 involved other dangerous weapons, like knives. Another 32 cases involved assault using hands, fists or feet to inflict harm on another.

Assaults within the city limits decreased by 6 percent.

Robberies over the past few years in the unincorporated areas have shown slight decreases, including in the number of robberies involving a firearm. Those cases make up 30 of the 54 robberies reported last year compared to 31 of 56 robberies the year before.

More people have instead been involved in strong-arm robberies — those involving bodily force — with the number showing slight increases each year. They’ve gone up from 11 in 2013 to 19 last year.

The number of property crimes — which include burglary, theft and larceny — dropped by about 9 percent to 1,732, with slight decreases noted for each category.

Property crimes also decreased within the city limits, although theft numbers within Lafayette increased slightly.

Arsons in the parish reduced from 13 in both 2013 and 2014 to seven last year.

Adult arrests in the parish decreased from 1,820 in 2014 to 1,649 last year, and juvenile arrests decreased by almost 100 last year to 391.

Follow Lanie Lee Cook on Twitter, @lanieleecook, or contact her by phone at (337) 534-0825.