1991 AIME Problem 6

Suppose r is a real number for which

\left\lfloor r+\frac{19}{100}\right\rfloor+\left\lfloor r+\frac{20}{100}\right\rfloor+\left\lfloor r+\frac{21}{100}\right\rfloor+\cdots+\left\lfloor r+\frac{91}{100}\right\rfloor=546

Find \lfloor 100 r\rfloor. (For real x,\lfloor x\rfloor is the greatest integer less than or equal to x.)