The amount of vacant office space in the Salt Lake area in the first quarter of 1988 dropped to 21.33 percent from 22.6 percent in the same quarter a year ago, according to figures released by Coldwell Banker Commercial Real Estate Services.

Coldwell officials said the decline in the vacancy rate occurred entirely in the downtown Salt Lake area, where the vacancy rate dropped from 21.9 percent in the first quarter of 1987 to 20.08 percent in the first quarter of 1988. The suburban vacancy rate remained almost unchanged at 23.8 percent.The latest survey shows that in the first quarter there was a total of 11.9 million square feet of office space in the Salt Lake area. Of that amount, 4 million square feet of space are located in the suburban area, a drop of 253,826 square-feet from a year ago.

In the downtown area, there are 7.9 million square feet of space, an increase of 311,762 square feet from the first quarter a year ago, Coldwell officials said.

The survey includes 92 suburban and 92 downtown buildings but doesn't include any government or medical facilities, single owner/occupied buildings nor any structure with less than 20,000 square feet of space.

To compare the Salt Lake area office space vacancy rate with other areas, they provided these percentage figures with the first number the downtown rate and the second figure the suburban rate: Albuquerque, 18.5 and 19.1; Denver, 29.9 and 27; Las Vegas, 14.4 and 21.1; Phoenix, 19 and 25.6; Portland, Ore., 18.6 and 19.8; Seattle, 11.1 and 20.7; and Tucson, Ariz., 19.1 and 26.8.

The survey showed that 45.2 percent of all industrial space is used for manufacturing, 36.9 percent in the wholesale/retail trade; 8.8 percent in transportation; 4 percent in services; and 4.9 percent for other purposes.