As of December 31, 2018 and 2017, the fully diluted share count for purposes of calculating our market capitalization was approximately 1,100 million and 1,086 million, respectively.
Impact of Currency Fluctuations on Results of Operations
In 2018, approximately 48% of our revenues were denominated in currencies other than the U.S. dollar. Because our results are reported in U.S. dollars, we are subject to significant foreign currency risks. Accordingly, changes in the rate of exchange between the U.S. dollar and the local currencies in the markets in which we operate (primarily the euro, British pound, Japanese yen, Israeli shekel, Canadian dollar, Polish zloty, Argentinean peso, Turkish lira and Russian ruble) impact our results.
During 2018, the following main currencies relevant to our operations decreased in value against the U.S. dollar (each on an annual average compared to annual average basis): the Argentinian peso by 37%, the Turkish lira by 22% and the Russian ruble by 7%. The following main currencies relevant to our operations increased in value against the U.S. dollar: the euro by 5%, the Polish zloty by 5%, the British pound by 4%, the Japanese yen by 2%, the Hungarian forint by 2% and the Swiss franc by 1%.
As a result, exchange rate movements during 2018, in comparison with 2017, positively impacted overall revenues by $152 million and positively impacted our operating income by $4 million.
Commencing in the third quarter of 2018, the cumulative inflation in Argentina exceeded 100% or more over a3-year period. Although this triggered highly inflationary accounting treatment, it did not have a material impact on our results of operations.
Liquidity and Capital Resources
Total balance sheet assets were $60,683 million as of December 31, 2018, compared to $70,615 million as of December 31, 2017.
Our working capital balance, which includes trade receivables net of SR&A, inventories, prepaid expenses and other current assets, trade payables, employee-related obligations, accrued expenses and other current liabilities, was negative $186 million as of December 31, 2018, compared to negative $384 million as of December 31, 2017.
Accrued expenses, as of December 31, 2018, were $1,868 million, compared to $3,014 million as of December 31, 2017. The decrease was mainly due to lower legal settlements of approximately $670 million, a milestone payment of $150 million to Labrys and a decrease in accrued restructuring expenses of $150 million.
Investment in property, plant and equipment in 2018 was $651 million, compared to $874 million in 2017. Depreciation was $676 million in 2018, compared to $632 million in 2017.
Cash and cash equivalents and short-term and long-term investments, as of December 31, 2018, were $1,846 million, compared to $1,060 million as of December 31, 2017. The increase was mainly due to proceeds from the issuance of senior notes, proceeds from the sale of our women’s health business, proceeds from the working capital adjustment with Allergan and the legal settlement with Rimsa, as well as other free cash flow generated during the year, offset by debt repayments as discussed below.
Our cash on hand that is not used for ongoing operations is generally invested in bank deposits, as well as liquid securities that bear fixed and floating rates.
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