HERE from Ultimos Noticias giving all the details; 52 are related Chavez and already 11 directed at Nick Ripe! Caracas Chronicles reminds us that "in only eighteen of those cases, the authorities have released any details to the public." Despite all this there has not been a single attempt, not one single trial and - obviously - not one single conviction. Needless to say it's always the far right, usually Colombian, usually ex Colombian President Alvaro Uribe and often the evil empire. I'm no Obama fan but how do you answer "Is President Obama so weak that decisions are made for him in the United States to kill a Latin American head of state without his knowing it?". I noted there was no talk of any attempt in 2012 [edit: see update below]...what with Krusty's poor health perhaps they thought it would have seemed a bad show to invent another plot to threaten to kill him. (the image - click to enlarge - shows all the info in a handy graph)
Update: a further hat-tip to Kepler (whose blog is well worth a read) who pointed out that I was wrong, there was an 'attempt' in 2012.