J. Schlotman
Analyst · Deutsche Bank
Thanks, Rodney, and good morning, everyone. IDs came in at 2.4%. As Rodney said, we've been in environments like this before, and we will continue to focus on growing households, growing units and making sure we are delivering the right value proposition for our customers.
Inflation was nonexistent in the first quarter. Lower inflation has persisted and, in fact, was slightly deflationary without pharmacy. When you add pharmacy back in, we had approximately 30 basis points of inflation. This is the lowest we have seen in the last 6 years.
During the quarter, trips per household were up and units per basket declined. This, combined with more households, led to positive tonnage growth.
Operating costs, excluding fuel and Roundy's, were 4 basis points better in the first quarter. Operating, general and administrative expenses were 11 basis points better and grew by approximately 2.9%. Rent and depreciation were a combined 7 basis points worse.
We continue to work diligently to keep operating costs in check. As you know, this is the fuel we use to run our Customer 1st strategy, and as Rodney just said, this is an area where our to-do list is longer than our done list.
Now for an update on retail fuel. In the first quarter, the average retail price of a gallon of gas declined by $0.45 compared to last year. Our cents per gallon fuel margin was approximately $0.143 compared to $0.116 in the same quarter last year. On a rolling 4 quarters basis, we were at $0.182 this year compared to $0.184 last year. We expect this downward trend to accelerate as we cycle some very strong margin quarters for the rest of the year.
Our first quarter net earnings per diluted share increased 12.9% to $0.70 compared to $0.62 during the same period last year. This result was helped primarily by our operating results and higher fuel margins during the first quarter. A lower LIFO expense and share buybacks also contributed to the EPS growth.
Our integration with Roundy's is well underway. Synergies are coming together nicely. We are beginning to focus on the physical assets in Wisconsin while continuing to open new Mariano stores in Chicago. Roundy's associates share our deep commitment to putting our customer first, which makes it easy for us to work together as one team.
For our corporate brands portfolio, we are off to an exciting start on the new innovation in 2016. Last quarter, we told you that we had just introduced Simple Truth household and personal care products, expanding our popular natural and organics line into a true lifestyle brand. Customers have responded enthusiastically as both sales and unit volume have exceeded our expectations in all categories. We continue to launch new Simple Truth offerings in laundry, household, baby and health and beauty care.
We also continue to push the boundaries of culinary trends with new Private Selection spices, marinades, condiments and cooking sauces. Customers are savoring global flavors in our delicious Private Selection products such as Korean black garlic kalbi marinade and Peruvian Aji Amarillo hot sauce.
During the first quarter, corporate brands represented approximately 27.9% of total units sold and 25.9% of sales dollars, excluding fuel and pharmacy.
The company's net total debt to adjusted EBITDA ratio increased to 2.12x compared to 2.09x during the same period last year. This result illustrates our commitment to use free cash flow to both grow our business and return cash to shareholders while remaining -- while maintaining an appropriate level of leverage for our credit rating.
Over the last year, Kroger used free cash flow to repurchase $1.1 billion in common shares, paid $397 million in dividends, invest $3.6 billion in capital and merged with Roundy's for $866 million. Kroger's strong EBITDA performance resulted in a return on invested capital for the first quarter of 14.08%, excluding Roundy's, compared to 14.03% for the first quarter of 2015. Our balance sheet is as strong as ever.
I will now provide a brief update on labor relations. We recently agreed to new contracts covering store associates in Houston, Indianapolis, Portland and Roanoke. We are currently negotiating contracts with UFCW for store associates in Little Rock, Nashville and Southern California. 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 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 continue to expect identical supermarket sales growth, excluding fuel, of approximately 2.5% to 3.5% for 2016. This reflects lower inflation as well as Roundy's results, which are an approximate 30 basis point headwind to identical supermarket sales growth.
For full year net earnings, we expect 2016 range of $2.19 to $2.28 per diluted share. As Rodney said earlier, based on current fuel margin trends, we expect to be at the low end to midpoint of our guidance range. We expect fuel margins will be at or slightly below the 5-year average.
Shareholder return will be further enhanced by a dividend that is expected to increase over time. And thinking about the cadence of our quarterly results compared to our long-term 8% to 11% guidance, we believe that the second quarter will be the toughest quarter with slight growth over 2015. Keep in mind the second quarter last year grew by 26%. Both the third and fourth quarters will be at the low end to midpoint of the range.
We continue to 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.
Finally, we continue to expect Kroger's full year LIFO -- full year FIFO operating margin in 2016, excluding fuel, to slightly expand compared to 2015 results.
Now I will turn it back to Rodney.