The 40% growth from donors giving $10,000 to $100,000 excludes anonymous donations, for reasons discussed in footnote 10. It includes both restricted and unrestricted donations processed by GiveWell. For information on donor giving by size category, see tables in the "Restricted donations: by donor size" and "Unrestricted donations: by donor size" sections of this blog post.
 For information on returning donors, see the table in the "New donors and returning donors" section of this blog post.
 We can attribute donations to some of our marketing and outreach efforts reasonably well, such as new donors giving as a result of podcast ads. However, in some cases, we don't have (or don't yet have) complete information to allow us to attribute donations. In other cases, we don't have compelling information about the counterfactual behavior of donors.
We feel reasonably confident that the majority of growth in 2019 was organic, based on preliminary calculations taking these ambiguities into account. However, we have a high level of uncertainty about the precise degree to which organic and proactive marketing and outreach efforts each contributed to our growth.
 The $54.1 million does not yet include funding we expect to receive from the workplace giving platform Benevity. Extrapolating from donations made on Benevity in the last five years, we expect to process an additional $700,000 to $800,000 from donors using this platform in 2019.
 Donations that are not made through GiveWell but are attributable to our work include (1) gifts made directly to each of our 16 top and standout charities that donors report as due to GiveWell and (2) gifts made through our partner organizations, such as Effective Altruism Funds, Effective Altruism Foundation, Founders Pledge, RC Forward, Effective Altruism Australia, and Norway Effective Altruism. Additional details on our partner organizations are in our 2018 metrics report.
 We break donors into size categories based on their total annual donations. A donor who gave $900 to GiveWell Top Charity A in March 2019 and $200 to GiveWell Top Charity B in December 2019 would be considered part of the $1,000-$10,000 size category.
 By default, we don't share the names of any of our donors publicly. Donations that are reported as "anonymous" here are anonymous to GiveWell: we don't know who made them. Donors may intentionally or unintentionally make anonymous donations to GiveWell in a number of ways, including the following non-exhaustive list: selecting the option to "make my donation anonymous" on our cryptocurrency donation form; making a securities donation or bank transfer donation (if the name isn't included as part of the transfer by the bank) without reporting information to us; donating from a donor-advised fund, where the fund's name is distinct from the donor's name and the donor doesn't report name or address information to us; and more.
It is very challenging for us to tell if an anonymous donation was made by someone who has made other donations (anonymously or non-anonymously). As a result, we do not track our anonymous donors by the total amount of their individual donations in a given year and therefore exclude them from the size buckets in this and subsequent tables.
 We received an unusually high level of unrestricted support in 2018 because Open Philanthropy provided GiveWell with an additional $2.45 million in operating support to cover the costs of operating Open Philanthropy from October 2016 to May 2017, while Open Philanthropy was still a part of GiveWell.
 As reported in Appendix 3 of our complete 2018 metrics report, excluding Good Ventures (Open Philanthropy), donors giving $1 million or more to our recommended charities (directly to charities and via GiveWell) accounted for a total of approximately $14.2 million in 2016, $8.5 million in 2017, and $18.6 million in 2018. Donors giving $1 million or more to recommended charities via GiveWell accounted for $1.3 million in 2016, $1.7 million in 2017, and $0 in 2018; see the table of restricted donation totals by donor size in the blog post.
We guess that as in previous years, donors who gave over $1 million in 2019 primarily gave directly to our recommended charities and are not well represented in the total donations processed by GiveWell.
 Open Philanthropy is a philanthropic organization with which we work closely and a major supporter of our top charities. Excluding donations from Good Ventures (Open Philanthropy), donors giving $1 million or more accounted for approximately $18.6 million of the total $61.0 million in non-Good Ventures (Open Philanthropy) money moved in 2018. See the first table under "Money moved by size of donor" in our blog post on money moved and web traffic in 2018.
 We have an excess assets policy that specifies that once we surpass a certain level of unrestricted assets, we will grant out the excess rather than continue to hold it ourselves. In addition, some funds we originally receive as unrestricted support may later be restricted by the donor or due to GiveWell's "single revenue cap," an informal rule we adopted that says no one revenue source should provide more than 20% of our operating funding each year. Additional details on the rationale and how we've applied this rule are in Draft of GiveWell Summary, Clear Fund Board Meeting - July 29, 2019, slide 13.