J. Schlotman
Analyst · Wolfe Research
Thanks, Rodney, and good morning, everyone. As Rodney said, wow, what a year. We exceeded all 4 of our financial performance commitments for the year. Identical supermarket sales and net earnings per diluted share growth, FIFO operating profit margin and return on invested capital were all better than our annual and long-term guidance. Market share growth continued, improving by 40 basis points, with 17 of 20 markets outlined by Nielsen POS plus data up and just one market down.
We had a lot of unique items in last year's fourth quarter, which make comparisons more complicated, so I'd like to spend the next few minutes discussing the story behind the numbers for our fourth quarter and fiscal year and to give you some color on those and the current operating environment.
There's a lot of speculation about inflation or deflation or disinflation. We believe a deeper dive is required when the operating environment has increased volatility. When you look at identical supermarket sales, you should not come to the conclusion that less inflation is fundamentally a bad thing. In fact, if you look at our real growth in the fourth quarter, that is, identical supermarket sales less inflation, this year's fourth quarter result was stronger than last year's fourth quarter when identical sales were over 6%. Tonnage stayed strong at over 3% unit growth during the quarter, and the strong tonnage allowed us to grow FIFO gross profit dollars, excluding fuel and Roundy's, by 4.4% in the quarter. All but one supermarket department had positive identical supermarket sales, excluding fuel during the quarter. Our natural foods, deli and produce departments led the way. The meat department was slightly negative due to 5% deflation in the category. This deflation has allowed retail prices to retreat or increase their purchases. As a result of strong tonnage, the meat department had a great quarter with strong FIFO gross profit dollar growth. This is what we often refer to as good deflation.
Our operating costs as a rate of sales were down for the 11th consecutive year. However, they were up 23 basis points in the fourth quarter. This calculation excludes retail fuel operations and Roundy's and excludes a $60 million contribution to the Kroger Co. Foundation and $55 million contribution to the UFCW pension plan in last year's fourth quarter and a $30 million contribution to that same plan in this year's fourth quarter.
There were several expenses in the quarter that won't continue at the same rate in future quarters, including chargebacks related to the transition of our payment systems to EMV that we expect to level out throughout 2016. We also saw higher pension costs and health care costs due to an increase in the number of claims and higher health care cost claims. That occurred during the fourth quarter. All that said, we can and will do a better job in some expense categories, including shrink, completing our EMV rollout and benefit costs.
In December, we said that volatility in weekly fuel costs would influence our fourth quarter results. That was true for the fourth quarter as our cents per gallon fuel margin was approximately $0.169 compared to $0.234 in the same quarter last year. Fuel in the fourth quarter only contributed about half as much net earnings per diluted share as compared to last year's fourth quarter. For the full year, the cents per gallon fuel margin was roughly $0.174 compared to $0.19 last year.
Our fourth quarter net earnings per diluted share increased 9.6% to $0.57 compared to $0.52 during the same period last year. This result was helped by the lower tax rate and lower LIFO expense, but our strong real growth contributed to our results.
Our 2015 cash flow generation was strong, allowing us to make $3.3 billion in capital investments during the year, excluding mergers, acquisitions and purchases of leased facilities. We repurchased $703 million of stock and returned $385 million to shareholders through our dividend. Net operating working capital declined $451 million, which also enhanced cash flow. Our net total debt to adjusted EBITDA ratio came in at 2.08x compared to 2.14 during the same period last year, even while investing approximately $870 million in our merger with Roundy's late in the year. Our balance sheet is as strong as ever.
I'll provide a brief update on labor relations. In 2016, we will negotiate agreements with UFCW for store associates in Houston, Indianapolis, Little Rock, Nashville, Portland, Southern California and Fry's in Arizona. Our objective in every negotiation is to find a fair and reasonable balance between competitive costs and compensation packages that provide solid wages, good quality affordable health care and retirement benefits for our associates. Kroger's financial results continue to be pressured by rising health care and pension costs, which some of our competitors do not face. Kroger and the local unions, which represent many of our associates, have a shared objective: Growing Kroger's business and growing it profitably, which will help us create more jobs and career opportunities and enhance job security for our associates.
Turning now to our 2016 guidance. We expect identical supermarket sales growth, excluding fuel, of approximately 2.5% to 3.5% for 2016, reflecting the lower inflationary environment. For full year net earnings, we expect 2016 to range from $2.19 to $2.28 per diluted share. Where we fall within the range will be primarily driven by the actual fuel margins. We expect margins will be at or slightly below the 5-year average with continued volatility. We expect our core business in 2016 to grow in line with its long-term net earnings per share growth rate of 8% to 11%. Shareholder return will be further enhanced by a dividend which is expected to increase over time.
In thinking about the cadence of our quarterly results compared to our long-term 8% to 11% guidance, the first quarter, we would expect to be at the midpoint to high end; the second quarter, below that range, and keep in mind, 2015 grew 26% for earnings per share last year; the third quarter, at the midpoint; and the fourth quarter at the midpoint.
We expect capital investments, excluding mergers, acquisitions and purchases of leased facilities to be in the $4.1 billion to $4.4 billion range for 2016.
We expect Kroger's full year FIFO operating margin in 2016, excluding fuel, to expand slightly compared to 2015 results.
Now I will turn it back to Rodney