Estimates of flowering plants that require pollination by animals are between 78% in temperate regions and 94% in tropical regions. However, only a fraction of these is pollinated by bees.
Considering only the crops used for human food consumption, some 75% require pollination by animals but this is only essential for 41 crops (36%). However, the bulk of human food (60%) is cereals, which do not require pollination by animals; this means that about 35% of plants used for human consumption require animal pollination.
How many of these plants require pollination by bees has not been estimated accurately. However, most animal pollination involves insects (but let's not discard birds and bats!) among which bees, hoverflies, and butterflies are the most common pollinators. Honey bees (Apis mellifera) in particular may provide some 14% of the overall pollination services in agricultural production since most of the bee pollinator species are bumblebees and other wild bees.
In economic terms, the value of pollinator services represents some 12% of food production, mainly by increasing the yield of fruits, vegetables, and nuts, with some authors estimating that if insect pollination were to fail, economic losses would be about 8% at most.