In the first half of this morning's session on US currency, the weighted average dollar exchange rate on deals with today's settlements amounted to RUR31.10, which is the same as yesterday. This rate remained unchanged for a third consecutive day. Meanwhile, commercial traders pointed to a sag in today's trading activity against the day before. Moreover, the low and the high of today's deals also stay put within 31.10 RUR/USD. Experts believe today's slump is mostly due to yesterday's large-scale operations as well as to the Central Bank's strict control over dollar rate fluctuations.