With any school, this will vary year to year and major to major. A good number of Cal Tech undergraduates go directly to PhD programs, so this sort of data may not be very meaningful for Cal Tech. If you are a high school student, I would not focus on jobs right now, I would focus on what college has the programs you want to study and what the research opportunities on campus are like. Cal Tech will beat any school out there for on campus research opportunities, except maybe MIT. Every student at Cal Tech can get onto a research project. This is not true at the very top U of Cal schools, for instance, where As may be needed to compete for on campus research opportunities.