Please narrow the scope of your question a little please. There are several levels of state appeals courts - several levels of federal appeals courts - several tax appeals courts - etc - etc....
Individual appeals are heard by three-judge panels. According to 2009 statistics (the most recent available as of January 2011), there were 181 active seats allocated to the thirteen US Court of...
In 2010, a total of 361,323 cases were filed in US District Courts; of those, 78,428, or 21.7%, were criminal cases and 282,895, or 78.3%, were civil cases. There were 55,992 appeals filed in the US...
The question is somewhat unclear. The court system of the various US states are similar in makeup to that of the federal system. In the state court system Circuit Courts are equivelant to the US...