You are often presented with tables describing the availability (uptime) for different resources. The opposite value would be the unavailability (downtime).

I really think that it would be better to show downtime instead of uptime, since it is easier to comprehend for most of us. Compare 99.9917% to 0.0083%.

Another benefit is that you can skip to show the 0% values, which will be understandable and natural, while skipping the 100% values may not be.

I would argue that the values in the downtime column in the table below, is much, much easier to get a grip of than the values in the uptime column. You can easily understand the magnitude of the values in the downtime column, while you probably need to make an implicit subtraction for each value when looking in the uptime column.

Another thing when using uptime value is that the uptime values are probably (always?) converted to downtime values, to understand the actual number of seconds/hours/days a resource is down (unavailable).

When displaying downtime, you can also make the table even more readable, by skipping useless zeroes:

Conclusions

So my recommendation is to always present downtime values instead of uptime values.