Infrastructure bottlenecks are among the largest inhibitors of economic growth in Bangladesh. The World Bank estimates that Bangladesh must spend $7.4 billion to $10 billion a year until 2021 to bring its power grids, roads and water supplies up to the standard needed to serve its growing population. The transportation sector alone will require between $36 and $45 billion of investments. Cement sales rose to about 33 million tons in the year, the highest on record, from about 30 million tons posted annually in recent years. Cement consumption grew 12 percent in 2018, way ahead of 8 percent to 10 percent average annual growth recorded in the last decade. The construction sector is playing an increasingly strong role in the economy amid continued urbanization and an array of large infrastructure projects undertaken by the government. It is one of the 15 major sectors that contribute to the gross domestic product (GDP). The sector posted 9.92 percent growth in 2017-18, up from 8.77 percent in the previous fiscal year, according to the state-run Bangladesh Bureau of Statistics (BBS). The sector's share to the GDP increased to 7.50 percent in the last fiscal year, which was 7.36 percent in 2016-17. The value of the economic activities in the sector was Tk. 73,595 crore in the last fiscal year. Some 3.43 million workers are now employed in the sector.