Hard to say.
The most common cause for SSL/TLS handshake failure is an inability to agree upon a common protocol and cipher. Because the protocol/cipher suite presented by the client is going to vary widely from client to client, and the suite supported by the server is going to vary widely from server to server, there's no way to do a real statistical analysis.
There are real numbers available for things like supported protocols and ciphers. Those can be used to infer things like failure rates for older browsers (IE6, Java 6). And then there's actual breakage like Microsoft's ServerKeyExchange problem - quantifiable as the result of an intersection between two pieces of software, but how often to they intersect in the real world? Hard to say, and not measured.