Analyzing depreciation on PP&E

The following note is taken from the 2004 Annual Report of ExxonMobil Corporation:

Dec. 31, 2004

Dec. 31, 2003

Historical
cost

Accumulated
depredation

Historical
cost

Accumulated
depreciation

millions of dollars)

Upstream

$148,024

$62,013

$138,701

$58,727

Downstream

62,014

29,810

59,939

29,566

Chemical

21,777

10,049

20,623

10,115

Dther

10,607

6,767

10,052

6,557

Total

$242,422

$108,639

$229,315

$104,965

In the upstream segment, depreciation is on a unit-of-production basis, so depreciable life will vary by field. In the downstream segment, investments in refinery and. . . manufacturing facilities are generally depreciated on a straight-line basis over a 25-year life and service station buildings and fixed improvements over a 20-year life. In the chemical segment, investments in process equipment are depreciated on a straight-line basis over a 20-year life. Accumulated depreciation and depletion totaled $133 783 million at the end of 2004 and $124 350 million at the end of 2003.

Required

Based on the above note, answer the following:

(a) By 2004, what percentage of the upstream segment costs have been depreciated? Assume no salvage value and assume that in 2005, no upstream acquisitions or divestitures take place. If the upstream PP&E are used to produce 10% of their capabilities, what would be the depreciation expense and net book value at the end of 2005?

(b) By 31 December 2003, assuming a 20% salvage (residual) value, on average, what is the age of the chemical PP&E?

(c) Assuming no divestiture or retirement of assets, what was the depreciation expense for all PP&E in 2004?