Hello, MS2 here. Depends on how interested in the school you are. Applying as OOS is definitely a long shot. For my class, UCD interviewed a total of 7 OOS students and matriculated 6 (I don't know how many submitted a secondary). Class of 2026 had 17 OOS interviews with 5 matriculating. I applied from OOS, and my only ties to the area were my husband's extended family. I am UMR and from a rural community though, so my experiences likely fit what they were looking for.
In terms of how many get a secondary, usually its around 2500-3000 total (varies based on overall number of applicants and fit). About 500 or so interviews are offered each year (again, could be more based on number of overall secondaries submitted and fit).