Asphalt Paving and Supply, Inc. (AP&S), has been in business in the Prescott/Prescott Valley community since 1983, providing paving and related civil construction services to the private and public sector. The company has a rich and diverse history that ranges from parking lot construction up to airport runway improvements. In July of 2003, AP&S along with a related business, Earth Products, was acquired by McCormick Inc. of Fargo, N.D. McCormick Inc. is a holding company that wholly owns and controls the activity of several construction enterprises. Since that time, we have made several subsequent acquisitions in the construction sector and aggregate mining business. To date, we have invested well over $10 million in acquiring existing Arizona based businesses, to firmly secure our competitive position.
With the initial acquisition, and each subsequent acquisition, we have strategically expanded the business to capitalize on a much broader market mix. The business unit today is some 400 percent larger in annual revenue generation. Although this rapid growth has been exciting and challenging, we have never moved beyond our qualified skill set at any one time, either in the public or private sector. We have been professionally responsible with the types of projects that we have engaged in as we have expanded. A valuable part of our strategy has been responsible hiring decisions. Knowing what type of talent will be required and securing the necessary individuals before the need arises has been a critical part of our strategic planning. Starting with a base core of personnel, we have continually hired and /or acquired the necessary individuals needed for any specific sector of our industry, prior to competing in that sector. These local personnel resources coupled with those available throughout our multi state operations, allow us to broadly compete in the industry. The businesses under the McCormick banner are Northern Improvement Company, Roberts Construction Company, McCormick Construction Company, and Asphalt Paving and Supply, Inc. (also known as Arrowhead Materials). Principals of our business were some of the early contributors to the drum dryer technology development in the early 1970s. The basis of that technology is now utilized in the vast majority of asphalt production plants worldwide.
Northern Improvement Company, our largest operation, is now a fourth generation, privately held, heavy/highway contracting business that has operated continuously for over 74 years. We have provided civil construction services in several states throughout the west, and mid-west during that 74 year span. Northern Improvement, as well, has a very diverse history and background. We hold the recognition as one of the very first construction firms to place over a mile of concrete paving in a single operation going back to 1959. We have successfully placed and completed thousands of miles of asphalt paving, concrete paving, concrete structures (including bridge construction), almost 16,000 miles of rural waterline (using our own designed plow train technique), mine shaft reclamation, environmental reclamations, commercial building site preparation, and residential site preparation. We have constructed heavy structural concrete flood walls to protect Port Arthur Texas, and have a division solely targeted to Power Plant construction. That division has completed many power plant expansions as well as new construction, including the required structural concrete foundations. Our municipal and private operations have included underground utilities, curb, gutter and sidewalk installation, catch basins, box culverts, headwalls, dirt work and paving. Northern Improvement has often been listed in Engineering News Records Top 400 Contractors. Collectively, the McCormick entities produce between 700,000 and 900,000 tons of Hot Mix Asphalt in any one calendar year.
In addition to Asphalt Paving and Supply, the McCormick group has also owned and operated McCormick Construction Company in Bullhead City for over 30 years. The two Arizona operations often collaborate on projects, combining personnel and equipment. Just since the turn of the century, McCormick Inc. companies have successfully completed well over $1 billion of construction activity; over $500 million in just the last 3 years. We have virtually unlimited bonding capacity, and revolving credit lines of over $10 million.