Local angleIn Vancouver, the Postal Service delivered packages the past two Sundays and will again be delivering this Sunday, said Vancouver Postmaster Scott Foster. Four carriers from the downtown post office and five from the East Vancouver office will be making deliveries from 8 a.m. to 4:30 p.m., Foster said. The rare Sunday deliveries are needed this year due to an unusually high volume of packages sent by mail, he said. In recent years, mail carriers have had fewer and fewer letters to deliver. Demand has dropped so much that the U.S. Postal Service, which lost $5 billion in the 2013 fiscal year, tried to get Congress’ approval to stop Saturday letter deliveries.So it came as a surprise when the Chicago post office announced last week that local carriers would deliver packages seven days a week in the two weeks before Christmas — including this Sunday — to keep up with a larger-than-expected boom in demand for holiday shipping.“Why the growth? Two words: online shipping,” said Mark Reynolds, Postal Service spokesman for the Chicago District. “A lot more online business is coming to us than in years past.”Though the number of pieces of first-class mail, which makes up the largest share of the PostalService’s revenue, fell from 91.7 billion in the 2008 fiscal year to 65.8 billion in the 2013 fiscal year, the number of package shipments has been rising. This year, the Postal Service handled 3.7 billion of them, up from 3.1 billion in 2009.