Year Ended December 31,
(in thousands of U.S. dollars, except calendar-ship-days)
2019
2018
Revenues
943,917
776,493
Voyage expenses
(402,294)
(381,306)
Vessel operating expenses
(208,601)
(209,131)
Time-charter hire expense
(43,189)
(19,538)
Depreciation and amortization
(124,002)
(118,514)
General and administrative expenses
(36,404)
(39,775)
Write-down and loss on sale of vessels
(5,544)
170
Restructuring charges
—
(1,195)
Income from vessel operations
123,883
7,204
Equity income
2,345
1,220
Calendar-Ship-Days (1)
Conventional Tankers
22,350
21,226

text: Operating Results – Teekay Tankers
text: The following table compares Teekay Tankers’ operating results, equity income and number of calendar-ship-days for its vessels for 2019 and 2018.
text: (1) Calendar-ship-days presented relate to owned and in-chartered consolidated vessels.
text: Teekay Tankers' income from vessel operations increased to $123.9 million in 2019 compared to $7.2 million in 2018, primarily as a result of: • an increase of $129.3 million due to higher overall average realized spot tanker rates earned by Teekay Tankers' Suezmax, Aframax and LR2 product tankers; • an increase of $3.5 million due to improved net results from Teekay Tankers' full service lightering (or FSL) activities from more voyage days and higher realized spot rates earned;
text: • an increase of $3.4 million resulting from lower general and administrative expenses primarily due to non-recurring project expenses incurred in 2018; • a net increase of $2.3 million primarily due to the delivery of three Aframax and two LR2 chartered-in tankers in late 2018 and throughout 2019, partially offset by the redeliveries of various in-chartered tankers to their owners in the second and third quarters of 2018; and • an increase of $1.2 million as a result of restructuring charge incurred in the prior year;
text: partially offset by
text: • a decrease of $10.2 million due to a higher number of off-hire days in 2019 resulting from dry dockings and higher off-hire bunker expenses compared to the prior year; • a decrease of $6.9 million due to lower revenues and loss on the sale of one Suezmax tanker in 2019 and the write-down of two Suezmax tankers that were classified as held for sale at December 31, 2019; and • a decrease of $6.4 million due to the amortization of first dry dockings for various former Tanker Investments Ltd. (or TIL) vessels subsequent to Teekay Tankers' acquisition of TIL in late 2017.
text: Equity income increased to $2.3 million in 2019 from $1.2 million in 2018 primarily due to higher earnings recognized in 2019 from the High-Q Investment Ltd. joint venture as a result of higher spot rates earned in 2019.

Questions:
question: What led to the increase in Equity income in 2019?
answer: primarily due to higher earnings recognized in 2019 from the High-Q Investment Ltd. joint venture as a result of higher spot rates earned in 2019.
question: What is the change in Revenues from, 2019 to 2018?
answer: 167424
derivation: 943,917-776,493
scale: thousand
question: What is the change in Voyage expenses from, 2019 to 2018?
answer: 20988
derivation: 402,294-381,306
scale: thousand
question: In which year was revenue less than 800,000 thousands?
answer: 2018
derivation: locate and analyze revenue in row 3
question: What is the value of Conventional Tankers in 2019?
answer: 22,350
scale: thousand
question: What is the value of Conventional Tankers in 2018?
answer: 21,226
scale: thousand