Automobile firms such as Tata Motors, Maruti Suzuki, M&M, Bajaj Auto, Hero MotoCorp and TVS Motor will declare their sales numbers for September from Monday. There are concerns auto sales may have grown at a slower-than-expected pace due to a weaker-than-expected monsoon and a squeeze in funding from non-banking financial companies. The rising costs of fuel and higher insurance costs may have also impacted sales, feel analysts.