Changes in property and equipment account for the years ended December 31, 2021, 2020 and 2019 are as follows:

	Cable and wire facilities			Central equipment			Network facilities			Buildings			Vehicles, furniture and other network equipment			Information origination and termination equipment			Land improvements			IT systems and platforms			Security platforms			Property under construction			Total
	(in million pesos)
As at December 31, 2019
Cost		201,652			2,800			321,798			28,128			29,241			30,906			4,597			50,654			17			46,167			715,960
Accumulated depreciation, impairment and amortization		(161,534	)		(2,172	)		(211,288	)		(22,560	)		(23,169	)		(18,707	)		(270	)		(44,125	)		(1	)		—			(483,826	)
Net book value		40,118			628			110,510			5,568			6,072			12,199			4,327			6,529			16			46,167			232,134
Year Ended December 31, 2020
Net book value at beginning of the year		40,118			628			110,510			5,568			6,072			12,199			4,327			6,529			16			46,167			232,134
Additions (Note 4)		915			155			2,124			238			1,548			2,771			102			991			—			63,060			71,904
Disposals/Retirements		(12	)		—			(114	)		(212	)		(59	)		—			(265	)		(1	)		—			(16	)		(679	)
Reclassifications		6,116			(707	)		(31,539	)		(263	)		4,030			10,979			(70	)		(5,893	)		24			17,312			(11	)
Transfers and others		21,066			—			42,477			897			(455	)		5,614			11			6,576			76			(76,262	)		—
Translation differences charged directly to cumulative translation adjustments		—			—			(1	)		—			(1	)		—			—			(1	)		—			—			(3	)
Adjustments		9			871			(700	)		28			125			1			53			(122	)		—			(201	)		64
Depreciation of revaluation increment on investment properties transferred to property and equipment charged to other comprehensive income		—			—			—			(1	)		—			—			—			—			—			—			(1	)
Depreciation and amortization		(9,922	)		(398	)		(11,154	)		(1,282	)		(4,664	)		(14,224	)		(10	)		(862	)		(24	)		—			(42,540	)
Net book value at end of the year		58,290			549			111,603			4,973			6,596			17,340			4,148			7,217			92			50,060			260,868
As at December 31, 2020
Cost		205,338			3,134			298,169			23,647			41,856			46,885			4,427			23,868			104			50,060			697,488
Accumulated depreciation, impairment and amortization		(147,048	)		(2,585	)		(186,566	)		(18,674	)		(35,260	)		(29,545	)		(279	)		(16,651	)		(12	)		—			(436,620	)
Net book value		58,290			549			111,603			4,973			6,596			17,340			4,148			7,217			92			50,060			260,868
Year Ended December 31, 2021
Net book value at beginning of the year		58,290			549			111,603			4,973			6,596			17,340			4,148			7,217			92			50,060			260,868
Additions (Note 4)		1,306			906			141			145			570			5,678			43			23			145			80,026			88,983
Disposals/Retirements		(9	)		(1	)		(81	)		(27	)		(52	)		—			(163	)		—			—			—			(333	)
Reclassifications		—			1,850			—			2,795			55			—			—			—			—			(4,554	)		146
Impairment losses recognized during the year (Note 5)		(27	)		—			(121	)		—			—			—			—			—			—			—			(148	)
Transfers and others		22,641			—			30,328			629			195			10,077			145			4,900			107			(69,022	)		—
Translation differences charged directly to cumulative translation adjustments		—			—			1			—			(1	)		—			—			1			—			—			1
Adjustments		8			—			—			(8	)		—			—			—			—			—			—			—
Depreciation and amortization (Note 3)		(10,676	)		(552	)		(23,282	)		(1,091	)		(2,124	)		(5,245	)		(10	)		(3,635	)		(166	)		—			(46,781	)
Net book value at end of the year		71,533			2,752			118,589			7,416			5,239			27,850			4,163			8,506			178			56,510			302,736
As at December 31, 2021
Cost		229,160			5,896			327,195			26,838			40,586			62,595			4,451			27,099			355			56,510			780,685
Accumulated depreciation, impairment and amortization		(157,627	)		(3,144	)		(208,606	)		(19,422	)		(35,347	)		(34,745	)		(288	)		(18,593	)		(177	)		—			(477,949	)
Net book value		71,533			2,752			118,589			7,416			5,239			27,850			4,163			8,506			178			56,510			302,736

Interest capitalized to property and equipment that qualified as borrowing costs amounted to Php1,582 million, Php1,597 million and Php1,455 million for the years ended December 31, 2021, 2020 and 2019, respectively. See Note 5 – Income and Expenses – Financing Costs – Net and Note 29 – Notes to the Statements of Cash Flows. The average interest capitalization rate used was approximately 4% for each of the years ended December 31, 2021 and 2020 and 5% for the year ended December 31, 2019.

Our net foreign exchange differences, which qualified as borrowing costs, amounted to Php29 million for the year ended December 31, 2021 and nil for each of the years ended December 31, 2020 and 2019.

The cost of fully depreciated property and equipment that are still being used in the Group’s operations amounted to Php77,201 million and Php73,995 million as at December 31, 2021 and 2020, respectively.

As at December 31, 2021, the estimated useful lives of our property and equipment are as follows:

See Note 3 – Management’s Use of Accounting Judgments, Estimates and Assumptions – Estimating useful lives of property and equipment.