Half of those
「I've gone overseas ten times, but half of those trips were for work.」
half of them / half
10回 = ten times
以上 = more than, over
行ったこと went (to), have been (to)
が = but, however
そのうち半分 = half of (those, them), half
仕事 = work
海外 = abroad, overseas
I've been overseas more than 10 times, but half of those (times) were for work.
I've gone abroad over 10 times, however, half were on business.