The disabled treaty and LatAm and the Caribbean

As a service to the public (so to speak) the following is a list of Latin American and Caribbean countries and what they have done regarding the "Convention on the Rights of Persons with Disabilities". The source comes from this U.N. website and the list is written from least to most action taken by governments:

No action
Bahamas
Belize
Grenada
Haiti
Saint Kitts and Nevis
Saint Lucia
Saint Vincent and the Grenadines
United States of America
Venezuela

Signed convention only
Barbados
Colombia
Guyana
Uruguay

Signed convention & optional protocol
Antigua and Barbuda
Argentina
Bolivia
Brazil
Chile
Costa Rica
Dominican Republic
Guatemala
Paraguay

Ratified convention
Cuba
Honduras
Jamaica
Nicaragua

Ratified convention & protocol
Ecuador
El Salvador
Mexico
Panama
Peru

What observations can I draw from this? Here are five quick points:

1. Just over one-quarter of states have yet to sign the convention. I expected a lower figure though I see that most of those countries are small and/or developing.
2. Of that list of countries who haven't signed two stick out: the U.S. and Venezuela. From the get go it was obvious that the U.S. would not sign to the treaty despite participating during several Ad Hoc committee sessions. Venezuela does surprise me since they seemed to be active during Ad Hoc committee sessions and their government has placed such a strong emphasis on social services.
3. The Colombian delegation was one of the most passive ones during the Ad Hoc committee sessions I attended. (I'll explain why another time; all that I will say for now is that I was not proud of their attention to distractions). Thus, imagine my shock when I find that they at least signed the convention.
4. The five countries that ratified the convention & protocol where very active during the Ad Hoc committee meetings not only through their government representatives but also via NGOs.
5. Fun facts: Jamaica was the first country to ratify the treaty in March 2007 while Ecuador's ratification last month allowed the treaty to go into effect.
   

Could more countries from the region ratify the treaty? I honestly don't know though that can certainly change in the upcoming months.