This appears to be Survey Sampling International, you can check them out at surveysampling.com If you do not wish to speak with these people and you have the ability to block numbers, then you will want to block the following:
From their website: SSI (www.surveysampling.com) is the premier global provider of sampling, data collection and data analytic solutions for survey research, reaching respondents in 78 countries via Internet, telephone, mobile/wireless and mixed-access offerings. Additionally, SSI staff operates from 26 offices in 18 countries, to offer CATI, questionnaire design consultation, programming and hosting, online custom reporting and data processing. SSI serves more than 3,000 clients worldwide.