but the biggest impetus has not been any law but the good dog owners putting pressure on those who do not pick up. Peer pressure works wonders.

Jack, If you say so.  But I wonder why Peer pressure was not more effective prior to the leash law!

As far as on leash I can say that close to 95% of dog owners that are residents abide by the law with the other 5% inadvertently finding their dogs off their property. [I am sure there may be a few exceptions] Unfortunately the biggest offenders of leaving a dog off leash are still the non resident owners coming down on a visit to their second home.

I assume that those percentages are based upon your own observation in your own circle of travel.  I personally have no supportive data but I am satisfied with the current situation in my neighborhood.  Evidently there are still problems in some areas.

with the other 5% inadvertently finding their dogs off their property.

My observation prior the the leash law was there was very few "inadvertent" unleashed dogs.  They were almost all deliberate.  It was also quite deliberate when dog owners did not pick up after their dogs.

I believe the leash law has been effective.  I also believe that the peer pressure from  responsible dog owners that yourself has also helped.

Norm