No correlation apparent between strict state gun laws and homicide rates

I tried to see, as Eugene Volokh once did, whether strict state gun laws are associated with lower homicide rates. Overall homicide rates, not, as has been done before, gun homicides only. Below is a chart of my results. On the x-axis is how strong each state's gun laws are according to the Law Center to Prevent Gun Violence, and on the y-axis is the average homicide rate of all the states with each gun law score (of which there were 9 possible ones, ranging from A- to F, as detailed on the Law Center to Prevent Gun Violence's website linked above. I converted these scores into numbers from 1, corresponding to F, to 9, corresponding to A-.) The homicide rates were taken from the Death Penalty Information Center. As you can see there is no positive correlation at all between these two variables. Looking at them using Excel and typing in "=correl" in an adjacent cell, it seems like there is, if anything, a slight negative correlation here. This peculiar result seems to be in line with previous analyses on this subject, e.g. by Factcheck.org, although not with respect to suicide, where stricter laws are associated with lower overall rates.