pre_text: Item 6. Selected Consolidated Financial Data The following table presents selected consolidated financial data as of and for the five-year period ended December 31, 2019. Our past results of operations are not necessarily indicative of our future results of operations. The following selected consolidated financial data is qualified in its entirety by, and should be read in conjunction with, “Management's Discussion and Analysis of Financial Condition and Results of Operations” and the consolidated financial statements and the notes thereto included elsewhere herein. Consolidated Balance Sheet Data:
table: As of December 31,
table: 2019 2018 2017 2016 2015
table: (In thousands)
table: Cash and cash equivalents $19,505 $18,017 $22,553 $26,838 $35,128
table: Working capital $1,116 $6,356 $7,646 $14,643 $16,046
table: Total assets $54,538 $43,424 $45,672 $53,530 $68,579
table: Stockholders' equity $10,863 $14,059 $13,078 $18,064 $21,387
question: Analyse this data from a financial earnings document. What is the average value of working capital from 2015 to 2019?