The National Resident Matching Program (NRMP) has published a 290-page summary [Characteristics of Applicants Who Matched to Their Preferred Specialty in the 2014 NRMP Main Residency Match (5th edition)] of the 2014 match, the latest year for which complete information has been analyzed.
The number of US graduates participating in that year's match was 17,374 compared to 16,896 graduates of other schools including non-US IMG's (7334), US IMGs (5133), DOs (2738), US graduates from previous years (1662), fifth pathway students (15), and Canadian grads (14).
From the Main Match Results Data for categorical general surgery in 2014:
Another way to look at it is that of a total of 17,374 US seniors in the match 922 (5.3%) matched in surgery while at 283 (1.7%) of 16,896 "others" matched in surgery. Of course many factors can influence whether you match or not.
The average USMLE Step 1 score of US seniors who matched in general surgery in 2014 was 232 ± 13 and for Step 2 was 245 ± 10. A US senior with a Step 1 score of 200 has a slightly better than 45% chance of matching compared to any applicant in the “other” (independent) category where a Step 1 score of 200 would result in about an 18% chance of matching. An “other” applicant with a 260 score on Step 1 has about a 60% chance of matching in categorical surgery while a US senior with the same score has close to a 100% chance. The figure below compares Step 1 scores and match rates for the two groups:
Applicants who matched had somewhat higher amounts of self-reported research experience and publications than those who did not match. Not in the NRMP data are other important characteristics such as medical school attended, year of graduation, current employment status, and US clinical experience.
A paper published ahead of print in the American Journal of Surgery analyzed some of the same data and found that although surgical programs have filled at a rate of almost 100% for over a decade, the percentage of categorical positions filled by US seniors has declined at a rate of 0.5 percentage points per year. In 2014, 76.5% of general surgery positions were filled by US seniors compared to a high of 89% in 1995. The downward trend is similar for match rates in all non-general surgery specialties where the match rate for US seniors in 2014 was about 63%.
A figure from that paper shows that the non-US senior deficit in general surgery is increasingly being filled by US and non-US international medical graduates at similar rates (dotted and blue lines) and DO, Canadian and fifth pathway applicants (green dashed line). The solid black line represents all "others." The upper horizontal line indicates 24%.
In addition to reviewing the information above. I strongly advise you to look at the match results for your school if you can find accurate data. For example, one Caribbean med school, Ross University, lists 778 graduates who obtained a residency position in any specialty through the 2016 match. [The number who enrolled in the match and were unsuccessful in obtaining a residency is unknown.] Of the 778, 20 (2.6%) matched in categorical general surgery.
A total of 82 US IMGs matched in general surgery in 2016; 20 (24.4%) of them were from Ross. I'll do the math. That left 62 who matched in surgery from the rest of the 25 or more Caribbean schools and any other foreign school attended by a US citizen
Remember, statistics like these describe groups. Every applicant is unique. Your results may vary.
Addendum 8/5/16: See this post about the implications of the supposed doctor shortage on IMGs.