The chart shows the generally accepted levels of caffeine for each category of tea.
However, studies have shown that some blacks have less caffeine than greens. Since most teas have not been tested for their caffeine levels then we need to take these ranges with a grain of salt.
Suffice it to say that tea has less caffeine than coffee. Matcha will have the most, around 120mg, since the entire leaf is being consumed. This will equal a regular cup of coffee.
A note about yerba mate - In South America, this herb is typically consumed by adding approximately 5 tbs (or about 1oz. of leaf) to a gourd so the caffeine content is high. One study showed that if you use 5g of mate, then the caffeine is around 17mg. similar to green tea.
Gascoyne, Marchand, et.al History, Terroirs, Varieties 2011
Tea: for a cup use a level teaspoon, for a mug use a heaping teaspoon
Herbals: use 2 teaspoons or a tablespoon per cup/mug
Per the Brits: one teaspoon per person and one for the pot after rinsing it with hot water
The Asian method would be to rinse the leaves first, called 'awakening of the leaf', then do several short steeps:
Brew / Times
1st 20 secs 2nd 10 secs 3rd 10 secs 4th 10 secs 5th 20 secs 6th 30 secs 7th 40 secs 8th 60 secs
But remember, its a personal preference - find what works for you!