Okie,
Tens of thousands of people have avoided pneumonia by getting immunized, but unless you're in a vaccine trial, you'll probably never know if you were protected by the immunization or not. Large groups show lower incidences of pneumococcal pneumonia after receiving the vaccine than groups that did not receive the vaccine. There are a number of other agents that cause pneumonia however, (viruses, other bacteria, fungi, etc.), that would not be affected by receiving the pneumococcal vaccine. Unless you have other medical conditions that would predispose you to pneumonia, and would probably disqualify you from service, you probably wouldn't benefit much by receiving the pneumococcal vaccine. Getting an annual flu shot is probably about the best you can do.
R/