By 2008, over four million copies of her works had been sold.
He has sold more than 100 million copies of his works.
By 2004, an estimated more than 30 million copies of his works were sold.
Altogether, about 550 million copies of his works have been printed.
By 1642 in Munich alone, 170,700 copies of his works had appeared.
More than eight million copies of his works, published in over 36 languages, have been sold around the world.
Performing right societies don't provide physical copies of particular works.
I don't think there were many copies of Faraday's works sold in those days.
They may also be copies of famous works of art.
They got a bound, paperback copy of his collected works.