Developed and developing countries witnessed different rates of growth in mobile-phone subscription from 2000 to 2008. As the bar graph shows, the number of mobile-phone sub-scribers in developed countries rose steadily(稳步增长)from 0.7 billion in 2000 to one billion in 2008. By stark contrast(突出对比), cell phone users in developing countries soared from 0.4 billion to 4 billion in the same period.

What accounts for this disparity(差距，不同)? The answer involves two factors. The first reason is technology gap. Developed countries generally enjoy advanced technology, which enables them to popularize mobile phone ahead of developing countries. Another contributing factor is the difference in population size. As we know, developed countries usually have a small population but most developing countries a large. As the price of the mobile phone slides(下滑), more and more people in developing countries avail themselves of(利用)this service, which explains the substantial increase(大幅增长)in mobile-phone subscription in these countries since 2003.

From the case of mobile-phone subscription, we see that developing countries are quickly catching up(赶追)in science and technology, which is believed to be conducive to closing the gap between developing and developed countries.