Here is waitlist data from 2016 since 2017 is not available. Since UCI was overenrolled last year, I would think that very few were admitted last year. Your chances are dependent upon how many students SIR on May 1 so no way to predict from year to year.
Number of qualified applicants offered a place on waiting list: 8366
Number accepting a place on the waiting list: 4503
Number of wait-listed students admitted: 835
You can check the common dataset in Section C2 to see the previous years stats.
http://www.oir.uci.edu/campus-data.html