Get visitors by label and date via API

Im writing an application that uses Piwik data via the API and needs to query for data in a tabular fashion - visitors for each day for each label, to generate a table like this:

|      | 2016-11-20 | 2016-11-21 | 2016-11-22 |
| foo  | 300        | 400        | 123        |    
| bar  | 452        | 114        | 112        |

So far, my naive approach is to do an API request for each label like this:

https://demo.piwik.org/?module=API&method=API.getRowEvolution&idSite=7&period=range&format=json&date=2016-11-14,2016-11-20&apiModule=Actions&apiAction=getPageUrls&label=t

However, the requests take a long time, since each label is queried with its own HTTP request and a have potentially hundreds of labels.

I’ve looked into using the label parameter as an array (&label[]=foo&label[]=bar) or doing bulk URLs, but both seem clumsy to me. Is there a better way to get the data?