Here are some examples of Niche EPMVs / RPMs. Another example of why there is much more to RPMs than niche.

In Real Estate, one site earns $3 and another $159. This is U.S. traffic only.

Publishers often ask "what niche?" when they see EPMVs (revenue per thousand session) numbers. I'll give you a few examples of why comparing across different sites isn't helpful.

Niche: Tech
EPMV: $597

Niche: Entertainment
EPMV: $149

Niche: Home/garden
EPMV: $121 (June)
Monthly Revenue: $100,000 - $200,000

Niche: Dating & Relationships
EPMV: $173 (June)
Monthly Revenue: $50,000 - $100,000

Niche: Travel
EPMV: $86 (June)
Monthly Revenue: $25,000 - $50,000

I think these are pretty good, but I'm sure I can find ones that are much worse in the same niche. The differences include:

Commercial intent (writing about your favorite bicycle trails is different that writing about your favorite bicycle brand/model)
Engagement (some topics people are looking for a quick answer and they are done, other's the users are more engaged / spend more time/view more pages)
Audience (some sites get affluent U.S. users that command a high price from advertisers, others don't)
Device/circumstance (some queries drive more traffic from people on-the-go which may monetize lower - think "how to fix a flat tire on a civic" vs "best tires for a civic". Both auto niche.

There are many more, but all of these reasons is why you should be using an ad system that adapts to different circumstances vs treating every page and user the same.