Maybe Portland is losing its enthusiasm for scooters.

In the last week, there were fewer rides on a scooter than the week before, according to data released today by the Portland Bureau of Transportation.

In the first two weeks, there were 47,836 rides. In the third week, there was 48,419. In the fourth week, there were 43,786. And last week, for the fifth week, Portland was down to 38,192, according to data released by PBOT on Twitter.

The average length of a trip also declined.

City officials say it's unclear why, after a smashing start, enthusiasm for scooters went flat, then dwindled.

"Any number of factors could account for weekly or daily variations," says PBOT spokesman Dylan Rivera. "Since we have among the most complete data of any city in the United States, we're hoping to provide the public with a full understanding of the opportunities and challenges this new technology presents us with—after we have the data from the full 120-day pilot program."