Seems to me, the person is claiming that a linear trendline increasing causes "steadily" to be an appropriate proxy for "values went up and down some, but overall went up".
If we can agree that the trendline is linear and that it goes up, then yes, we can agree on "steadily".
However, if we observe that the actual data goes both up and down over a specified period, then no, the data cannot be characterised as "steady".
For those interested, perhaps I could suggest drawing a process capability chart? The sigma variation lines would seem to clearly demarc outliers.
If we can agree that the trendline is linear and that it goes up, then yes, we can agree on "steadily".
However, if we observe that the actual data goes both up and down over a specified period, then no, the data cannot be characterised as "steady".
For those interested, perhaps I could suggest drawing a process capability chart? The sigma variation lines would seem to clearly demarc outliers.