Furthermore, they suggest that patent mapping provides useful insights into a company's R&D strategy and can illuminate areas of technological drive arguing that this is perhaps the only source revealed competitive profiling of a company's technology. Bowonder et al, illustrate the analysis with various tables of patents from 1990 to 1999. With three main criteria used, total R&D spending measured, R&D spending as a percentage of sales (R&D intensity), number of patents granted, and spending on R&D for patent for each company. Bowonder et al. examine the R&D spending patterns of global companies by calculating the amount of total R&D spending, the number of patents granted to each company, and the cost per patent. This seems like a comprehensive and valid method of measuring what can be seen as a difficult task, given a company's intellectual rights and secrecy that normally surrounds its technology. It was agreed that it could illustrate areas of current technological interest, however patents take a long time to be awarded, possibly providing information on outdated trends. Although it would still benefit from looking at a company's overall patterns of R&D behavior, its competitive technology position, and the company's annual budgets. Also, the cost per patent