The total land area of Sarawak is nearly , making up 37.5 per cent of the total area of Malaysia, and lies between the northern latitudes 0° 50′ and 5° and eastern longitudes 109° 36′ and 115° 40′ E. Its of coastline is interrupted in the north by about of Bruneian coast. A total of its coastline have been eroding. In 1961, Sarawak including neighbouring Sabah, which had been included in the International Maritime Organization (IMO) through the participation of the United Kingdom, became joint associate members of the IMO. Sarawak is separated from Kalimantan Borneo by ranges of high hills and mountains that are part of the central mountain range of Borneo. These become loftier to the north, and are highest near the source of the Baram River at the steep Mount Batu Lawi and Mount Mulu. Mount Murud is the highest point in Sarawak.