Americans are rapidly becoming much more upbeat about the economy. Consumer sentiment leapt 13% in the first half of January from December‚ the University of Michigan said Friday. That came on the heels of a sharp rise in December‚ causing the index to surge a combined 29% from November‚ the biggest two-month increase since 1991. The pickup in sentiment was broad-based‚ spanning consumers of different age‚ income‚ education and geography. The recovery in sentiment “is likely to provide...