Dunnza and XXX its all about karma. I see some good things on the horizon for you guys. It is in fact incredibly rare for a ga company to repond to job applications given the sheer numbers of people sitting in syd mel bne trying to get a job by sending out letters. It really speaks volumes of your respective organisations. That is not to say that if a ga company doesn't reply that they are not a good organisation! As dunnza points out the number of letters received can be significant.
Polymer do not let these numbers put you off. 95% are people that will not leave home.They are the types that might be spotted regularly turning up to uni in uniform (the opposite sex thing you are queit stupid).
I worked for a ga company that was a bit out of the way once and was amazed at how few people actually knocked on the door looking for a job. Plenty of letters though. We only kept the ones that were near the minimum requirement or ones that showed promise (likely 1 page followed up with a call and a visit then an update).