Err, no, look closely you'll probably see a "-" sign before the number, most amps that show this sort of info start at low minus figures and go up to zero.
Decibel is a relative unit of measurement i.e. it shows how much one value is higher or lower than the other. in case of a receiver it is of signal level in relation to a 'reference' level. if the reference level is the maximum one the receiver can do, then signal attenuation below that max can be expreseed in dB, which is the case in your receiver.
dB can go up or down, depends in which direction levels are compared.
interesting thing about decibels is because they are logarithmic they add up logarithmically. e.g. for sound pressure (SPL) level, if one speaker plays at 100dB SPL, and you add another one that alone also plays at 100db SPL, the toal SPL will not be 200dB, but 106dB.