Around 62 percent of electrical estimators work within the estimating electricity installation industry and 15 percent work in the manufacturing industry. As part of an electrical estimate the cost and duration of future projects are accurately predicted. The information provided by an electrical estimating company is often used to develop cost information for owners or managers to enable them to make a bid on a project or decide on the profitability of a new project or product. It is necessary for electrical estimators to analyze and compile data on all the factors, which may influence costs such as duration of the project, special machinery requirements, materials, labor, and location. Accurate estimating is vital to a project, as inaccurate quotes can result in a firm losing a bid or losing money on a job that was not estimated accurately. An electrical estimating company will adhere to the National Electrical Code, which aims to protect the public. This code is reviewed around every three years using committee studies, improved installation procedures, better products and more advanced designs. It is necessary for anyone carrying out an electrical estimate to keep up to date with the latest developments within the field. This can make the role of the electrical estimators much more difficult, yet in return makes the work better, safer and more enjoyable. The majority of electrical estimators will divide up their electrical estimate into two parts, labor and materials. Estimating electricity installation costs can be hard as labor is always difficult to predict, due to so many factors affecting production such as poor work force management, late deliveries, strikes and bad weather. It is necessary for an electrical estimating company to carry out an accurate quantity take-off, in which wholesale prices, quotes for special items and any required subcontract prices will determine the material costs of the project. Materials usually account for 60 percent of estimating electricity installation costs.