DFDL to handle a decimal value?

[Roger L Costello]

My input contains a decimal value representing a latitude minutes.  Here are 
several legal values:

74
74.1
74.12
74.123
76.1234

As you can see, the value may be a whole number, or it may have a decimal point 
followed by 1-4 digits.

This works fine if the value is a whole number:

    <xs:element name="LatitudeMinutes"
                type="xs:decimal"
                dfdl:lengthKind="pattern"
                dfdl:lengthPattern="[0-9]{2}[0-9\.]*(?=([^0-9]))"
                dfdl:textNumberRep="standard"
                dfdl:textNumberCheckPolicy="strict"
                dfdl:textNumberPattern="00"
                dfdl:textStandardGroupingSeparator=","
                dfdl:textStandardDecimalSeparator="."
                dfdl:textStandardBase="10"
                dfdl:textNumberRounding="pattern">
    </xs:element>

But it fails if the value has a decimal point followed by digits.

This works fine if the value has a decimal point followed by digits:

    <xs:element name="LatitudeMinutes"
                type="xs:decimal"
                dfdl:lengthKind="pattern"
                dfdl:lengthPattern="[0-9]{2}[0-9\.]*(?=([^0-9]))"
                dfdl:textNumberRep="standard"
                dfdl:textNumberCheckPolicy="strict"
                dfdl:textNumberPattern="00.0"
                dfdl:textStandardGroupingSeparator=","
                dfdl:textStandardDecimalSeparator="."
                dfdl:textStandardBase="10"
                dfdl:textNumberRounding="pattern">
    </xs:element>

But it fails if the value doesn't have a decimal point followed by digits.

How to declare LatitudeMinutes so that it can parse any of the inputs shown 
above?