Prime jumbo mortgages were the hardest hit product in the slumping production environment of the first quarter of 2006, according to a new analysis and ranking by Inside Mortgage Finance. Prime jumbo volume dropped 36 percent from the fourth quarter of 2005 to just $99 billion, or 14.8 percent of total originations. That was more than double the speed of the slowdown in total mortgage originations, which fell 15 percent in the first quarter.… [Three data tables included]