Existing home sales in November drop for the first time in 5 months

After five consecutive months of gains, sales of existing homes turned lower in November. They fell 2.5 percent on a month-to-month basis to a seasonally adjusted annualized rate of 6.69 million units, according to the National Association of Realtors. Sales were a strong 25.8 percent higher year-over-year. CNBC's Diana Olick joins "Squawk on the Street" with the details.