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on a high level is the most popular phrase on the web.

at a high level 156,300,000 results on the web	on a high level 1151,000,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Capacity utilisation of the Union industry remained stable at a high level just below 90 %. That also includes the aim of keeping the price of tobacco products at a high level. Public health protection is only to be considered in connection with internal market harmonisation measures, albeit at a high level. The Presidency has also had contacts at a high level with many European Union partners. In the study looking at booster vaccination, antibody levels against rhinotracheitis herpesvirus and calicivirus infection remained stable at a high level or increased slightly. In the study looking at booster vaccination, antibody levels against rhinotracheitis herpesvirus, calicivirus infection and feline panleucopenia remained stable at a high level or increased slightly. We have every reason to believe that there's a breach, possibly at a high level. In the study looking at booster vaccination, antibody levels against rhinotracheitis herpesvirus, calicivirus infection and C. felis remained stable at a high level or increased slightly.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

at a high level

156,300,000 results on the web

on a high level

1151,000,000 results on the web

More popular!

Capacity utilisation of the Union industry remained stable at a high level just below 90 %.
That also includes the aim of keeping the price of tobacco products at a high level.
Public health protection is only to be considered in connection with internal market harmonisation measures, albeit at a high level.
The Presidency has also had contacts at a high level with many European Union partners.
In the study looking at booster vaccination, antibody levels against rhinotracheitis herpesvirus and calicivirus infection remained stable at a high level or increased slightly.
In the study looking at booster vaccination, antibody levels against rhinotracheitis herpesvirus, calicivirus infection and feline panleucopenia remained stable at a high level or increased slightly.
We have every reason to believe that there's a breach, possibly at a high level.
In the study looking at booster vaccination, antibody levels against rhinotracheitis herpesvirus, calicivirus infection and C. felis remained stable at a high level or increased slightly.

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