A once-popular children's doll is slowly declining in popularity. The quartic function f(x) - - 0.022x + 0.457x -2.492x4-5.279x + 87.419, where x is the number of years since 1993, can be used to estimate the number of dolls of this type that were sold (in thousands) during a given year from 1993 to 2003. Estimate how many dolls were sold in 2001. The number of dolls sold in 2001 was approximately (Round to the nearest thousand.)