Las Vegas Sands Corp. CEO Sheldon Adelson said he knew what question was coming: when would the steady and steep decline in the world’s most lucrative gambling market hit bottom? A corruption crackdown that has shaken up the up-until-recently skyrocketing gambling business in Macau, China has sped swift drops in revenue and activity there. Las Vegas Sands, a giant in the casino, hotel and convention business – particularly overseas – reported a first-quarter profit of $511.9 million, a 34 percent drop compared to the same period a year ago, hurt by lower revenue.