Tex. Civil Practice and Remedies Code § 33.003

(a) The trier of fact, as to each cause of action asserted, shall determine the percentage of responsibility, stated in whole numbers, for the following persons with respect to each person's causing or contributing to cause in any way the harm for which recovery of damages is sought, whether by negligent act or omission, by any defective or unreasonably dangerous product, by other conduct or activity that violates an applicable legal standard, or by any combination of these:

(1) each claimant;

(2) each defendant;

(3) each settling person; and

(4) each responsible third party who has been designated under Section 33.004.

(b) This section does not allow a submission to the jury of a question regarding conduct by any person without sufficient evidence to support the submission.