Looking on the internet deeply has found these results:

were highly concerned is the most popular phrase on the web.

were highly of concerned 10 results on the web	were highly concerned 11,710 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	Mar 10, 2014 ... Of the boys who were highly concerned with their weight, about half were worried only about gaining more muscle, and approximately a third�... Mar 18, 2013 ... A survey of more than 700 pregnant women by University College London (UCL) found a quarter were 'highly concerned about their weight�... Jun 15, 2012 ... Only 44% of all respondents were highly concerned about this issue. Among lower income (<$50,000/year) respondents, 52% were highly�... Sep 4, 2014 ... Within this subgroup, smokers who were highly concerned about gaining weight were more likely to avoid treatment to help them quit.

were highly of concerned

10 results on the web

were highly concerned

11,710 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

Mar 10, 2014 ... Of the boys who were highly concerned with their weight, about half were worried only about gaining more muscle, and approximately a third�...
Mar 18, 2013 ... A survey of more than 700 pregnant women by University College London (UCL) found a quarter were 'highly concerned about their weight�...
Jun 15, 2012 ... Only 44% of all respondents were highly concerned about this issue. Among lower income (<$50,000/year) respondents, 52% were highly�...
Sep 4, 2014 ... Within this subgroup, smokers who were highly concerned about gaining weight were more likely to avoid treatment to help them quit.