Robtree - I used a '???' because there are uncertainties.

The average is 300/year.
They talk about sometime achieving 24 interviews with 30 guys at some unknown time in the future.

Your assumption uses 600 guys a year. The only known hiring rate is 2x25 anticipated through summer 2014. If they keep that up for all of 2014 they're looking for 900 guys in the next 4 yrs, or 225/yr.

I'd find it surprising if they run 24x30 for the first 450(50% of 2014) off the street hires and then maintain 720 interviews to hire 122 off the street guys for each year after 2014.

Using the average hiring rate and maximum interview rate the acceptance level could be as low as 20%(ergo the ???). But during the previous cycle I think the acceptance rate was much higher.