Why does this query return many duplicates?

[chrismp]

I'm trying to find the number of home purchase loans originated in 2017 in Palm Beach County, Fla.

Here's a link to my query: https://api.consumerfinance.gov/data/hmda/slice/hmda_lar.html?%24select=county_name%2C+state_code%2C+county_code%2C+census_tract_number%2C+population%2C+loan_purpose%2C+loan_purpose_name&%24where=loan_purpose%3D1+and+action_taken%3D1+and+state_code%3D12+and+county_code%3D99+and+census_tract_number%21%3D%27%27+and+census_tract_number+is+not+null+and+as_of_year%3D2017&%24group=&%24orderBy=census_tract_number&%24offset=0&%24format=html

Many rows have the same census_tract_number. Why's that?

And what query must I run to find the the number of home purchase loans originated in 2017 in Palm Beach County, Fla.?