Oil capped its biggest weekly decline in almost three decades as concern that the collapse of global fuel demand will deepen outweighed talks between OPEC and Texas's energy regulator. Futures in New York tumbled 11% Friday, bringing the week's plunge to 29%, the biggest since January 1991. Some traders see demand shrinking as much as 10 to 20 million barrels a day as drivers stay home and flights are grounded across the world. Two of the three commissioners at Texas's oil agency are sceptica ....