How much power does a Silk Scarf raise?

Question

To a normal type with normal moves.

Answer 1

In Generation III, the Silk Scarf boosts the power of Normal moves by 10%. In Generation IV+, it boosts them by 20%.

The Silk Scarf's predecessor, the Pink Bow, is exclusive to Generation II and also boosts the power of Normal moves by 10%.

Silk Scarf (Bulbapedia)
Pink Bow (Bulbapedia)

Answer 2

20% increase. The type of the Pokemon doesn't matter, Silk Scarf will always raise Normal type moves by 20%. However, including STAB, you'll have gotten an 80% increase.

http://pokemondb.net/pokebase/68311/what-are-the-items-that-boost-moves-and-what-their-multipliers?show=68315#a68315

Comments

Don't mean 70%??
STAB (50%) + Silk Scarf (20%) = 70%