\begin{tabular}{lrrrr} \hline (US\$ millions) & 12/31/2016 & 12/31/2015 & 12/31/2014 & 12/31/2013 \\ Net income & $13,010 & $12,050 & $11,020 & $10,040 \\ Depreciation expense & 6,500 & 6,270 & 4,980 & 3,950 \\ Changes in working capital & 1,170 & 2,290 & 2,350 & 1,030 \\ \cline { 2 - 5 } Cash from operating activities & $20,680 & $20,610 & $18,350 & $15,020 \\ \cline { 2 - 5 } Capital expenditures & $(16,000) & $(14,480) & $(13,970) & $(12,280) \\ \cline { 2 - 5 } Cash from investing activities & $(16,000) & $(14,480) & $(13,970) & $(12,280) \\ Interest and financing cash flow items & $(320) & $(230) & $(390) & $90 \\ Total cash dividends paid & (3,580) & (2,820) & (2,510) & (2,170) \\ Issuance (retirement) of stock & (7,970) & (1,550) & (3,580) & (4,450) \\ Issuance (retirement) of debt & 1,540 & (70) & 3,960 & 4,050 \\ Cash from financing activities & $(10,330) & $(4,670) & $(2,520) & $(2,480) \\ \cline { 2 - 5 } Net change in cash & $(5,650) & $1,460 & $1,860 & $260 \end{tabular} \begin{tabular}{lrrrr} \hline (US\$ millions) & 12/31/2016 & 12/31/2015 & 12/31/2014 & 12/31/2013 \\ Net income & $13,010 & $12,050 & $11,020 & $10,040 \\ Depreciation expense & 6,500 & 6,270 & 4,980 & 3,950 \\ Changes in working capital & 1,170 & 2,290 & 2,350 & 1,030 \\ \cline { 2 - 5 } Cash from operating activities & $20,680 & $20,610 & $18,350 & $15,020 \\ \cline { 2 - 5 } Capital expenditures & $(16,000) & $(14,480) & $(13,970) & $(12,280) \\ \cline { 2 - 5 } Cash from investing activities & $(16,000) & $(14,480) & $(13,970) & $(12,280) \\ Interest and financing cash flow items & $(320) & $(230) & $(390) & $90 \\ Total cash dividends paid & (3,580) & (2,820) & (2,510) & (2,170) \\ Issuance (retirement) of stock & (7,970) & (1,550) & (3,580) & (4,450) \\ Issuance (retirement) of debt & 1,540 & (70) & 3,960 & 4,050 \\ Cash from financing activities & $(10,330) & $(4,670) & $(2,520) & $(2,480) \\ \cline { 2 - 5 } Net change in cash & $(5,650) & $1,460 & $1,860 & $260 \end{tabular}