FINANCIAL CONDITION, LIQUIDITY AND CAPITAL RESOURCES
All currency amounts are in millions unless specified
Selected cash flows for the years ended December 31, 2019, 2018 and 2017 are as follows:
Operating activities—The growth in cash provided by operating activities in 2019 and in 2018 was primarily due to increased earnings net of non-cash expenses, partially offset by higher cash taxes paid in 2019, most notably cash taxes paid on the gain on sale of the Imaging businesses.
Investing activities—Cash used in investing activities during 2019 was primarily for business acquisitions, most notably iPipeline and Foundry, partially offset by proceeds from the disposal of the Gatan business and the Imaging businesses. Cash used in investing activities during 2018 was primarily for business acquisitions, most notably PowerPlan.
Financing activities—Cash provided by/(used in) financing activities in all periods presented was primarily debt repayments/ borrowings as well as dividends paid to stockholders. Cash provided by financing activities during 2019 was primarily from the issuance of $1.2 billion of senior notes partially offset by $865.0 of revolving debt repayments and to a lesser extent dividend payments. Cash used in financing activities during 2018 was primarily from the pay-down of revolving debt borrowings of $405.0, partially offset by the net issuance of senior notes of $200.0 and dividends paid to shareholders.
Net working capital (current assets, excluding cash, less total current liabilities, excluding debt) was negative $505.4 at December 31, 2019 compared to negative $200.4 at December 31, 2018, due primarily to increased income taxes payable, deferred revenue, and the adoption of ASC 842, partially offset by increased accounts receivable. The increase in income taxes payable is due primarily to the approximately $200.0 of taxes incurred on the gain associated with the divestiture of Gatan. We expect to pay these taxes in the second quarter of 2020. The deferred revenue increase is due to a higher percentage of revenue from software and subscription-based services.
Total debt excluding unamortized debt issuance costs was $5.3 billion at December 31, 2019 (35.9% of total capital) compared to $5.0 billion at December 31, 2018 (39.1% of total capital). Our increased total debt at December 31, 2019 compared to December 31, 2018 was due primarily to the issuance of $500.0 of 2.35% senior unsecured notes and $700.0 of 2.95% senior unsecured notes, partially offset by the pay-down of revolving debt borrowings of $865.0.
On September 23, 2016, we entered into a five-year unsecured credit facility, as amended as of December 2, 2016 (the “2016 Facility”) with JPMorgan Chase Bank, N.A., as administrative agent, and a syndicate of lenders, which replaced our previous unse- cured credit facility, dated as of July 27, 2012, as amended as of October 28, 2015 (the “2012 Facility”). The 2016 Facility comprises a five year $2.5 billion revolving credit facility, which includes availability of up to $150.0 for letters of credit. We may also, subject to compliance with specified conditions, request term loans or additional revolving credit commitments in an aggregate amount not to exceed $500.0.
The 2016 Facility contains various affirmative and negative covenants which, among other things, limit our ability to incur new debt, enter into certain mergers and acquisitions, sell assets and grant liens, make restricted payments (including the payment of dividends on our common stock) and capital expenditures, or change our line of business. We also are subject to financial cove- nants which require us to limit our consolidated total leverage ratio and to maintain a consolidated interest coverage ratio. The most restrictive covenant is the consolidated total leverage ratio which is limited to 3.5 to 1.
The 2016 Facility provides that the consolidated total leverage ratio may be increased, no more than twice during the term of the 2016 Facility, to 4.00 to 1 for a consecutive four quarter fiscal period per increase (or, for any portion of such four quarter fiscal period in which the maximum would be 4.25 to 1). In conjunction with the Deltek acquisition in December of 2016, we increased the maximum consolidated total leverage ratio covenant to 4.25 to 1 through June 30, 2017 and 4.00 to 1 through December 31, 2017.
At December 31, 2019, we had $5.3 billion of senior unsecured notes and $0.0 of outstanding revolver borrowings. In addition, we had $7.7 of other debt in the form of finance leases and several smaller facilities that allow for borrowings or the issuance of letters of credit in foreign locations to support our non-U.S. businesses. We had $74.0 of outstanding letters of credit at December 31, 2019, of which $35.8 was covered by our lending group, thereby reducing our revolving credit capacity commensurately.
We may redeem some or all of our senior secured notes at any time or from time to time, at 100% of their principal amount, plus a make-whole premium based on a spread to U.S. Treasury securities.
We were in compliance with all debt covenants related to our credit facility throughout the years ended December 31, 2019 and 2018.
See Note 8 of the Notes to Consolidated Financial Statements included in this Annual Report for additional information regarding our credit facility and senior notes.
Cash and cash equivalents at our foreign subsidiaries at December 31, 2019 totaled $291.8 as compared to $339.0 at December 31, 2018, a decrease of 13.9%. The decrease was due primarily to the repatriation of $290.6 during the year and cash used in the acquisition of Foundry, partially offset by cash generated from foreign operations. We intend to repatriate substantially all historical and future earnings subject to the deemed repatriation tax.
Capital expenditures of $52.7, $49.1 and $48.8 were incurred during 2019, 2018 and 2017, respectively. Capitalized software expenditures of $10.2, $9.5 and $10.8 were incurred during 2019, 2018 and 2017, respectively. Capital expenditures and capitalized software expenditures were relatively consistent in 2019 as compared to 2018 and 2017. In the future, we expect the aggregate of capital expenditures and capitalized software expenditures as a percentage of annual net revenues to be between 1.0% and 1.5%.
Table:
 | 2019 | 2018 | 2017
Cash provided by/(used in): |  |  | 
Operating activities | $ 1,461.8 | $ 1,430.1 | $ 1,234.5
Investing activities | (1,296.0) | (1,335.1) | (209.6)
Financing activities | 177.0 | (388.1) | (1,170.0)


Question: What was the cause of growth in cash provided by operating activities in 2018 and 2019?
Answer: increased earnings net of non-cash expenses, partially offset by higher cash taxes paid in 2019, most notably cash taxes paid on the gain on sale of the Imaging businesses