import com.cloudbees.opscenter.analytics.reporter.items.AnalyticsJobProperty

def createdDateCompare = Date.parse("MM/dd/yyyy","05/25/2016")
jobs = Jenkins.instance.getAllItems();
def numberOfWorkflowJobs = 0
jobs.each { j ->
  if (j instanceof org.jenkinsci.plugins.workflow.job.WorkflowJob) {

    def analyticsJobProperty = (AnalyticsJobProperty)j.getProperty(AnalyticsJobProperty.class)
    if(analyticsJobProperty != null && analyticsJobProperty.created < createdDateCompare.time) {
      def jobCreatedDate = new Date(analyticsJobProperty.created)
      println j.name + " created on: " + jobCreatedDate
      return
    }
    numberOfWorkflowJobs++
  }
}

println "Number of workflow jobs: " + numberOfWorkflowJobs