There are more smiles on car lots across Tarrant County. A strong upward trend continued in July when the county’s auto dealers saw their sales surge once again.  Compared with last year’s dreary auto market performance, 2010 is looking pretty good.  Retail sales of new cars and pick-ups jumped nearly 20 percent in July, much nicer than the eight percent increase recorded for the four-county Dallas-Fort Worth region.  The nation-wide increase is about five percent.  Counting July, the first seven months of this year saw Tarrant County retail auto figures up nearly 16 percent over the same period in 2009 when annual sales plummeted to their lowest point since the 1980s.