As a side note, I've seen this infographic (Which appears to be fanmade):
They note that there are at least 30 hunters in the group (Though their count seems to include Ajay, Dieter, Carter, and Burke.)
However, I'm not sure where they're getting some of the deaths from.
It states that four hunters are killed when the Triceratops attacks the camp. However, Ludlow explicitly states to Malcolm, "My team is still intact. Sorry for the loss of your man."
Then they state that 9 hunters are killed during the Tyrannosaur attack on the creekside camp. I've only ever seen two direct deaths, Carter and Burke, not sure where they are getting the other 7 from.
They are close with stating 16 hunters going into the grass. However, in both overhead shots of the full group, I've counted 17. (So, Ajay plus 16 others.)
The biggest thing is that (as I previously mentioned above) the InGen team's size is (or appears to be) inconsistent. In a wide shot of the group on their trek (before Tembo and Ajay hear an offscreen dinosaur), it is nearly impossible to determine how many people are in the shot, since some hunters are seen walking side by side, and because the line is in the distance, its difficult to get an accurate head count.
My count for the InGen team is a total combined group of 22 (including Tembo, Ludlow, Dieter, etc.), 26 if you include Malcolm and his team when they group up. (This is more in case that my screencap head count may have double-counted extras who changed out of their ponchos, cause there are some who were wearing ponchos during the night walk scenes, but in the daytime break, no longer have them on.
(On an unrelated note, when Dieter walks over to Carter, you can see a hunter smoking a cigar. So..bloody jacket AND the cigar were potentially alerting the Tyrannosaurs? Especially since Sarah told Nick to not light up.)