Long Term Trends in Homicide - A Decline IS NOT from MORE GUNS!

I found the post and graphs below on a site called Marginal Revolution.  It is interesting in that it tracks comparative trends in homicides.  The point of this post is that countries which had a far lower rate in firearm deaths and homicides generally are also having declines in crime - without more guns.  Fewer guns equal fewer gun deaths, fewer mass shootings, fewer suicides, fewer firearm accidents and less violent crime generally, particularly lethal violence crime.
 An article from last August in the Guardian noted this (bold - my emphasis):

In 2009, New York City had the lowest number of murders since detailed FBI records began in 1963. There was a small increase last year but even so the total of 536 homicide victims was still well below the 2,245 murdered in 1990 when Times Square was infamous for peep shows and drug pushers, not the Disney Store.
Twenty years ago, the murder rate for the whole US was 9.8 per 100,000 people. It has fallen by nearly half, although it is still twice the rate in France.

and, statistics which support that it is not having MORE guns which reduces crime:

Anti-gun activists note that the cities with two of the sharpest falls in murder rates, New York and Washington, have enacted strict gun control laws by US standards. Yet Houston in Texas, where some regard it as criminal not to own a gun, has also seen a sharp drop in homicides.

and from the Guardian article on length of prison sentences reducing crime - this one is for our new friend Crunchy:

But Wilson adds that cannot be the sole explanation [length of jail sentences], as Canada has experienced roughly the same decline in crime without the same lengthening of prison sentences.

Now on to the Marginal Revolution site post:

Long Term Trends in Homicide Rates

by Alex Tabarrok on June 1, 2011 at 7:37 am in Data Source, Economics | PermalinkHere is a graph of American homicide rates, the earlier results should be taken with a grain of salt of course, but the trend is clear. N.B. These rates are per 100,000.
The American data is consistent with European data. Here is Table 2 from Manuel Eisner’s Long-Term Historical Trends in Violent Crime. Do note that some correction should be made for the fact that violence is less lethal when people are healthier and medical care is more effective.
The bottom line is that there has been a big and welcome decrease in homicide rates in Europe and America over the past several centuries. To put these numbers in perspective, however, note that the homicide rate in New Orleans today is 52 per 100,000 and in Detroit it’s 40 per 100,000 so even with a lower average there is lots of variation. Brazil today is around 22 per 100,000 not too far from America in the 19th century. The homicide rate in El Salvador is 71 per 100,000, in Jamaica (!) 60 per 100,000 and in Honduras 67 per 100,000 — all higher than fifteenth century Europe. Thus, the past was a more violent place but not so violent as to be unknown to the present.