June 16 (Reuters) - Lyft Inc (LYFT.O) said on Wednesday the number of drivers on its U.S. ride-hail platform was gradually increasing, resulting in reduced wait times for customers and a modest decrease in surcharge pricing as travel rebounds from pandemic lows. Lyft said active drivers on its platform had increased 10% since the beginning of May, adding that thousands of new drivers were activated over just the past two weeks. In data provided to Reuters exclusively, the company said passenger wait times across the United States were down around 15% on average compared with one month ago. Wait times in some major markets, including Austin, Texas; Miami and Philadelphia, were 25% to 30% shorter and down as much as 35% in Las Vegas. Serving the rebound in travel demand is crucial for Lyft, which has promised investors it will be profitable on an adjusted basis by the end of the third quarter in September. Longer wait times mean a loss of potential customers and lower revenue. Lyft declined to provide absolute figures for driver numbers and wait times. The company also warned that wait times and prices may continue to fluctuate as the rebound from the pandemic continues. Lyft and its larger rival Uber Technologies Inc (UBER.N) have been scrambling in recent months to bring back drivers to their platforms to serve a sudden uptick in rider demand as more Americans are vaccinated against COVID-19 and resume pre-pandemic travel. Uber and Lyft are trying to lure drivers back with additional incentives and the promise of temporarily higher earnings. The undersupply of drivers has led to a sharp increase in prices and long wait times in many U.S. cities, causing many ride-hail customers to vent their frustrations online. Lyft said on Wednesday that surcharge fares during peak demand - a measure the company calls Prime Time pricing - had declined 15% during the last week of May compared with the last week of March.