This blog originally appeared on Whittington Consulting's Online Results blog.Inbound marketing is an effective way to grow website traffic and increase your lead generation efforts. One of the many reasons this kind of marketing is effective today is because it is heavily data-driven. Whether you’re piecing out how to write a blog headline or figuring out your response rate for social media engagement, numbers are always available to guide your decision-making and provide context for why you do what you do. Email marketing — the process of keeping touch, educating and converting leads through email campaigns — is no exception. Email marketing statistics exist to help you write the most effective email from top to bottom, and they are always changing because new data is always available. So if you haven’t been up on the most updated information in email marketing since 2012 or 2013, here are the latest statistics available: Email is nearly 40 times better than Facebook and Twitter at acquiring customers. ( McKinsey & Company ) 73 percent of marketers think email marketing is core to their business. Marketers who think that email is a critical enabler of products and services has risen 18 percent since 2014 (from 42 percent to 60 percent). 20 percent of marketers say their business’ primary revenue source is directly linked to email operations. 43 percent of businesses have email teams of 2-3 people. 74 percent of marketers believe email produces or will produce ROI in the future. Click-through rates (47 percent), conversion rates (43 percent), and click-to-open rates (38 percent) are the top metrics used to monitor email marketing achievement. Nearly two-thirds of companies would like to improve their personalization (64 percent), marketing automation (64 percent), and segmentation (62 percent). (EConsultancy) 59 percent of marketers plan to increase their email marketing budgets in 2015. Email content and design (79 percent), campaign management (74 percent), and contact management (74 percent) rank as the three most critical aspects of an email. Marketers rank the 3 most effective aspects of an email as email content and design (66 percent), templates (59 percent), and quality control (58 percent). MailChimp reports straightforward, non-salesy email headlines outperform their opposites time after time. MailChimp also reports that short, descriptive headlines (under 50 characters) perform best overall and that list quality and list frequency can also play a major role in email marketing list performance. Salesforce finds that a one-column layout works best in both aware and responsive design. Finally, according to HubSpot, there’s no perfect formula for email length . It will vary according to your audience, the purpose of the email, and the kind of email it is. Newsletters (66 percent), promotional content (54 percent), and welcome series emails (42 percent) rank as the top three uses of emails. Mobile opt-ins (76 percent), birthday emails (75 percent), and transactional emails (74 percent), on the other hand, rank as the most effective emails. MailChimp data indicates that no single weekday is best for response and open rates. It also reveals that email opens peak between 9 AM and 12 PM and slowly decline over the rest of the day and evening. Find out more about open, click-through, and bounce rates according to your specific industry and company size by reading MailChimp’s 2015 Email Marketing Benchmark Report . 72 percent of US online adults send or receive personal emails via smartphone at least weekly ( Forrester ) In a May 2013 survey of US internet users showed that respondents spend more time per week with email than any other digital activity. According to Salesforce, 1/3 of marketers say their subscribers read emails on mobile devices at least 50 percent of the time. For Gmail users, the iPhone’s built-in mail program is the #1 email client for 34 percent of all Gmail opens. ( Litmus ) 48 percent of emails are opened on mobile devices. Only 11 percent of emails are optimised for mobile. 69 percent of mobile users delete emails that aren’t optimised for mobile. 64 percent of decision-makers read their email via mobile devices. (Forbes) 64 percent of people say they open an e-mail because of the subject line. ( Mark the Marketer via Workflow Max ). 76 percent of email opens occur in the first two days after an email is sent and the open rates of those emails are lower on weekends than on weekdays. ( Mark the Marketer via Workflow Max ). 72 percent of B2B buyers are very likely to share useful content via email. ( Mark the Marketer via Workflow Max ). Desktop and smartphone email opens happen most often between 10am and 4pm—during the typical workday. ( Harland Clarke ) Inspired to get to work on your next campaign? You should be. Email marketing is a cornerstone practice of successful inbound marketing. Now that you’re all caught up on the most recent email marketing statistics, you’re prepared to design even more effective email launches.