Aspirin is much more selective to COX-1 than to COX-2. You may find IC50s of many NSAIDs in this paper: Deleted research itemThe research item mentioned here has been deleted
NSAID stands for "non-steroidal anti-inflammatory drugs". This name was introduced in the 1950s to differentiate between the steroidal anti-inflammatory drugs (like Cortisone) and the class of anti-inflammatory analgesic compounds (NSAIDs). The later class is further divided into the non-selective COX-1/-2 inhibitors like ASS, Diclofenac, Ibuprofen, ... and the selective COX-2 inhibitors (Coxibes) like Celecoxib.