Visualize violent crime rates in the US with choroplethr package

Visualize violent crime rates in different US States with choroplethr package I have read choroplethr package from the blog post Animated Choropleths in R a few days ago. As a another visualization tool in R language, I want to try this one.
To install the latest stable release(CRAN) type the following from an R console:
To install the development version using the devtools package from github, type the following::
install_github("choroplethr", "trulia")
It's not interesting for me to run just example codes written in choroplethr package. Instead, I used other data from rMaps package as a quick data source and visualize it!
Now we can use violent crime rates data in the US included in rMaps package.
We can create animated choropleths as the following page:
In my case, we just process the data and visualize it as the following simple code:
# load packages
# initialization list and get years from violent_crime data
choropleths = list()
# Get years for loop
years <- sort(unique(violent_crime$Year))
# convert to level data
violent_crime$Crime <- cut(violent_crime$Crime, 9)
# Create choropleth component.
for (i in 1:length(years)) {
    df <- subset(violent_crime, Year == years[i])
    # We need to change the column names for choroplethr function
    colnames(df) <- c("Year", "region", "value")
    # Cut decimal off df$value <- round(df$value)
    title <- paste0("Violent crime rates: ", years[i])
    choropleths[[i]] = choroplethr(df, "state", title = title)
# Vizualize it!
The result is published via Dropbox as the following (image)link.