Getting back to the original circumstance (rookie agent) ... a synthesis of the responses from Karen, Deepak, and Jim covers the key variables. But since you're probably looking for some guidance, and not just "It depends", here's my twist.
(1) My experience, and that of about 5 others I know in different firms, track with Deepak: after a year, the "target level on average" is about one new application and one office action per week. If a firm wants in excess of 50 new applications/yr, clear out once you get a year's experience on your resume.
(2) In theory, your managing partner is supposed to distribute cases among the associates/agents such that you get a balance of easy and hard cases to attain the expected target.
(3) In practice, it doesn't work out that way. I know of one associate who did only office actions for his entire first two years. I (an agent) have ~80% new apps/20% office actions. The senior associate next door has the flip side, ~20% new apps/80% office actions.
(4) The factor that's going to impact you most is what Karen refers to as "cheap clients"/"generous clients". Translated into other terms, "cheap clients" = Megacorp clients with a large book of business at low flat rates, $X/new app, $Y/office action; "generous clients" = clients with real inventions and real funding who pay $Z/hr.
So, if the flat rate for a new app is $5K, and you start out with a billing rate of $150/hr, you are expected to crank out an app in 33.3 hr. If you are a senior associate and have a billing rate of $300/hr, you are expected to crank out an app in 16.7 hr. The times are inclusive of everything: the clock starts ticking when you open the case folder and stops when the app is filed. The actual allotted time is less, because the partner takes his cut for review; this cut is substantial if he bills $500/hr.
A new app has considerably more overhead than an office action (inventor interviews, preparation of figures, IDSs, declarations, misc forms). A new app also has a lot more uncontrolled variables: quality of the initial disclosure, availability and cooperation of the inventors. Office actions are also variable, but overall they are more tightly constrained than new apps and have less overhead. As Jim pointed out, except for trivial cases, even a highly competent agent/associate would be hard pressed to crank out a new app in 17 hr (especially when there is a minimum fixed overhead).
Net result: Senior associates get more office actions and a greater fraction of "easy" apps. Patent agents get more apps and more difficult ones at that. So here is the bizarre quirk of law office practice, as your billing rate goes up, you are allotted less time to complete the task. In theory, the added experience allows you to do the job faster. But that starts to level off after 2-3 yr; and there is still that fixed minimum overhead.
Of course, you can't do a good job under these circumstances. But the Megacorps clients don't expect you to. They just want to meet or beat their target metrics. That was the subject of another thread a while back, so I won't repeat it here.
So find out what the mix of clients is, hope you have some generous clients, and find out what it takes to get their cases assigned to you.