In general, the 6pm news reached its peak for almost 5 million viewers per day in the first month.
- It doesn’t make sense to signal this statement ‘In general‘, because it’s not general. It features data values taken from the x and y axes of the graph. Better to put this information in the detail section of your essay and signal it “In detail,“.
- You need to treat ‘reach a peak‘ as a phrasal verb. If you want to change the tense – and the tense will most likely be past simple tense – then you can modify ‘reach‘ (past: ‘reached a peak‘). Otherwise don’t mess with ‘a‘ and don’t mess with ‘peak‘.
- The preposition ‘for‘ is not right.
So, if you really are making a general statement, do this:
- In general, the popularity of the 6pm news reached a peak in the first month.
If you want to mention detail, then do this:
- In detail, the 6pm news reached a peak of almost 5 million viewers per day in the first month.
Pay careful attention to this pattern:
something + reached a peak (+ of + value x) (+ time expression)
If you don’t believe me, check out these examples!
And whatever you do, don’t write ‘reached the peak‘! That applies to climbers only, where ‘the‘ refers to the mountain that they happen to be climbing at the time!